Development and Validation of a Discriminative Quality ofLife Questionnaire for Osteoporosis (The OPTQoL)

EVA LYDICK,1 SHERYL ITKIN ZIMMERMAN,2 BARBARA YAWN,3 BETSEY LOVE,4

MICHAEL KLEEREKOPER,5 PHILIP ROSS,6 ALLISON MARTIN,1 and RICHARD HOLMES1

ABSTRACT

We report the development and validation of an osteoporosis-targeted quality of life questionnaire to measure theimpact of the disease in the general population. Frommultiple focus groups with women with osteoporosis, healthywomen at risk for osteoporosis, spouses and relatives of women with osteoporosis, and health care providers, weidentified over 300 potential items related to the disease. A lengthy questionnaire incorporated these items and wasadministered to a second large study cohort of 222 women with clinical osteoporosis (history of fracture, significantheight loss, and/or kyphosis); 101 women with known low bone mineral density levels that would categorize themas osteoporotic but who had not yet shown obvious physical manifestations of the disease; and 142 women withother conditions (such as arthritis, cancer, depression) expected to also have an impact on quality of life. Finalitems from among the original 300 were chosen for their demonstrated relationship with osteoporosis as measuredby clinical manifestations and low bone density and with quality of life measured by a standard genericquestionnaire, the SF-36. The final questionnaire contains 26 scored items in three domains—physical activity,adaptations, and fears—and six nonscored questions relating to osteoporotic changes and diagnosis. Thisinstrument is unique among osteoporosis-targeted questionnaires in that it attempts to measure the total impactof the disease on quality of life within a population at a single point in time. (J Bone Miner Res 1997;12:456–463)

INTRODUCTION

OSTEOPOROSIS is one of the nonfatal conditions cited byRudberg et al.(1) that leads more to changes in the

quality of life rather than to changes in the quantity of life.For osteoporosis and many other chronic conditions, lifeexpectancy alone is an inadequate measure of the impact ofthe disease. The usual emphasis on numbers of fractures isan incomplete accounting of osteoporosis. Common physi-cal and social outcomes of osteoporosis such as loss ofheight, digestive problems, kyphosis, depression, decreasedmobility, pain, and loss of independence lead to a chroni-cally decreased quality of life for the affected individual andcaregivers.(2,3)

We wished to quantitate the community impact ofchronic osteoporosis, not just the effect of acute fractures.Beyond assigning women to a category of osteoporotic ornonosteoporotic, we desired to assess symptoms and limi-tations associated with all levels of osteoporosis from severemultifracture disease to fears of future disease amongwomen with known low bone density or with a family historyof osteoporosis.As one of many chronic conditions associated with aging,

the effects of osteoporosis are not specific. Thus, our in-strument would need to focus on characteristics of partic-ular relevance to osteoporosis.(4) Based on a review of theliterature,(3) we viewed the most likely clinical conse-quences of osteoporosis as being decreased mobility, in-

1Merck Research Laboratories, West Point, Pennsylvania, U.S.A.2University of Maryland at Baltimore, Baltimore, Maryland, U.S.A.3Olmsted Medical Group, Rochester, Minnesota, U.S.A.4Providence Medical Center, Portland, Oregon, U.S.A.5Wayne State University, Detroit, Michigan, U.S.A.6Hawaii Osteoporosis Center, Honolulu, Hawaii, U.S.A.

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creased fear of falling and fractures, dissatisfaction withbody image, and respiratory and/or gastrointestinal prob-lems associated with severe kyphosis and/or height loss.We describe here the development and validation of an

osteoporosis-targeted quality of life questionnaire (OPTQoL)through phases of item generation, item reduction, andcontent and construct validation. This was a multicenterstudy that gathered information on all phases of the diseasefrom a diverse group of individuals. The instrument is notintended for clinical evaluation of disease interventions, butas a measure to help in understanding the natural history ofosteoporosis; as an aid in screening individuals for disease-related problems; and to provide further information dur-ing the decision making process for prevention and/or treat-ment programs.

MATERIALS AND METHODS

Development of the questionnaire involved three majorphases: item generation, item reduction, and preliminaryvalidation and pilot testing.(5) Focus groups of women,caregivers, and health professionals were the source of allitems, although review of the literature provided back-ground information for a standardized script used by themoderators of these groups. The second phase itemized theconcerns, fears, limitations, and clinical signs and symptomsmentioned by participants of the focus groups into an ex-tensive first generation questionnaire. Item validation andreduction followed from the responses to this lengthy ques-tionnaire by 465 women with and without clinical osteoporosis.The selection of items for the final questionnaire requiredin-depth analysis of the importance of each item in women’slives as well as the ability of responses to distinguish be-tween women with and without osteoporosis. These phasesin the development are discussed in more detail below.Each site investigator was required to obtain approval foreach phase of the study from the institutional review boardand informed consent from all participants from that site.

Focus groups

Four regional sites (Rochester MN, Baltimore MD, Port-land OR and Detroit MI) conducted focus groups. Moder-ators from each site attended a joint training session. Wedeveloped a standardized script to begin the focus groups.This script contained probing questions regarding the im-pact of osteoporosis on mobility, social and recreationalactivities, health, physical appearance and self image, emo-tions, outlook on life, concerns about the future, finances,and relationships with others. These questions were derivedfrom a review of the literature and from expert knowledge,but were to be used only as a starting point. Moderatorswere instructed to use these general questions to facilitatediscussion and ensure that a broad range of topics werecovered. Moderators were urged to probe for more specif-ics and were free to follow up other aspects that aroseduring the focus group.In addition to the moderator, a transcriber was also

present during the focus group session to make notes of

items introduced and discussed by the participants. Audiotapes of all focus groups were later reviewed for additionalitems. An “item” was a specific description of a task orfeeling that was expressed by one or several participants.Items could evolve as participants strove to best expresstheir feelings. If similar but distinct phrases were expressedby two or more participants, all phrases were kept as items.

Item reduction questionnaire

In a joint meeting of investigators and moderators fromall four centers, all identified items were reviewed andcategorized. In this joint meeting, the working group alsoadjudicated which were unique items and which were onlyinsignificant variations of one another. A lengthy question-naire was developed using all items considered to be unique.Within this questionnaire, for those items that were tasks,women were asked how frequently they performed the task;how important being able to perform the task was to themor how much the particular item affected their daily activ-ities; whether they had difficulty doing it and, if so, howmuch difficulty. For those items that were attitudes oradjustments, the items were made into statements to rateagreement. Most response options were three levels, withthe exception of agreement questions (4 levels) and a fewyes/no items. Altogether, this lengthy questionnaire askedover 600 questions regarding 300 items, although somequestions could be skipped based on initial responses.

Item reduction study cohort

Five centers participated in the second phase (HonoluluHI in addition to the four original centers). Centers wereeach asked to recruit approximately 100 women meetingpredetermined qualifications. We desired to include womenwith clinical osteoporosis, women with known low bonemineral density (BMD) but who had not yet experiencedfractures, height loss or kyphosis, and women from thecommunity with and without other known comorbidities.Particular emphasis was placed on obtaining women witharthritis because this common comorbidity would likelymimic osteoporosis in terms of functional limitations. Par-ticipants in the second phase were asked to complete a briefdemographic questionnaire, a medical history question-naire, the Center for Epidemiologic Studies DepressionScale (CES-D),(6) and the Medical Outcomes Study Short-Form General Health Survey (SF-36).(7,8) An intervieweradministered the long questionnaire of osteoporosis-relateditems. Besides recording the subjects’ responses, interview-ers were instructed to note those items that seemed to beunclear or ambiguous to the participants. However, inter-viewers were not permitted to interpret specific items forthe participant. Investigators also completed a short surveyon medical information specific to osteoporosis that wasavailable in the woman’s medical chart or otherwise known.This included information on fracture history, spine frac-tures discovered on X-ray, bone density measurements,observed height loss, and the investigator’s assessment ofkyphosis.For most analyses, women were categorized as one of the

QUALITY OF LIFE QUESTIONNAIRE FOR OSTEOPOROSIS 457

following: (1) having clinical osteoporosis, (2) having lowBMD but no clinical manifestations of osteoporosis, or (3)all others. Clinical osteoporosis was defined as a wrist, hip,or vertebral fracture following little or no trauma, loss of 2cm of height or more, or definite kyphosis as judged by theinvestigator (woman could not bring her head and shoul-ders even with the spine). Low BMD was 2 or more stan-dard deviations (SD) below peak bone mass as specified bythe manufacturer of the densitometer used.In addition, several categories of comorbidities were de-

fined. Cancer was any history of cancer other than basal orsquamous cell skin cancer or cancer in complete remission.Arthritis was a self-reported history of arthritis treated withgold, steroids, methotrexate, or nonsteroidal anti-inflam-matory drugs. Three centers were asked to specifically re-cruit individuals with diagnosed arthritis. Women from allcenters completed the medical history questionnaire. Symp-tomatology indicative of depression was coded for womenscoring 16 or more on the CES-D scale. Mobility impair-ment was defined as a positive response to any of thefollowing questions: paralysis, weakness, or trouble walkingfrom stroke, Parkinson’s disease, pain with walking orshortness of breath from heart problem, shortness of breathor wheezing when active or walking, amputation, or recentjoint replacement surgery.

Item reduction

Items that few women reported having difficulty doing(mean score less than “some” difficulty) or that few womenthought important (mean score less than “somewhat impor-tant”) or which 5% or more women did not answer or foundinapplicable were eliminated from further consideration.Responses for remaining items were tabulated, stratifyingby basic group (clinical osteoporosis, low BMD, all others)and age. Tasks reported as more difficult for women withclinical osteoporosis (a difference of 0.2 or greater in meandifficulty between women with clinical osteoporosis andother women within each decade of age, where a differenceof 1.0 represents the change from “a lot” of difficulty to“some” difficulty or a change of “some” to “no” difficulty)were retained for further consideration.Items related to fears about osteoporosis and/or osteo-

porotic changes were chosen on face validity because therewas no evidence that women with clinical osteoporosiswould be more apt to fear future fractures and changes thanwomen known to have low BMD. For these items, we didexpect women with known low bone density to indicategreater levels of concern than women with bone density ofnormal or unknown values.(9)

Efforts were made to choose the appropriate comparisonbetween the item under consideration and the comparisondomain of the SF-36. For example, for items relating tophysical function, the SF-36 domains of physical functionwere used for comparison; for those items relating to adap-tations, domains of social or emotional functioning or vi-tality/fatigue usually provided the most relevant compari-son. From that subset of questions that fulfilled therequirements for both an age-adjusted relationship withSF-36 domains and with clinical osteoporosis, the responsecategory was modeled by multiple regression as a function

of age, comorbidities, and basic group (clinical osteoporo-sis, low BMD, and all others). Those items that still showeda consistent relationship with clinical osteoporosis aftercontrolling for arthritis, mobility impairment from otherconditions, cancer, and depression were kept. After theseanalyses, there were approximately 60 remaining items.The goal was to reduce the questionnaire to approxi-

mately 30 questions. Factor analysis separated these 60items into four domains initially: physical activities, adap-tations, fears now, and fears future. Both principal compo-nent and varimax rotation were used. When two questionswithin a domain appeared similar, that question that bestdistinguished between women with and without clinical os-teoporosis was retained. On two occasions, questions werecombined into a single item.The majority of the fears questions relating to fractures

or future impairment from osteoporosis were highly asso-ciated with clinical osteoporosis and low BMD and hadstrong face validity. About half of the questions in eachdomain were eliminated based on some (slight) superiorityof one over the others, although all of them showed similarperformance on almost all attributes. Remaining questionsfrom the two fears domains were combined into a singledomain.

Performance characteristics of final questionnaire

Scores for the three final domains were calculated for the465 women participating in the item reduction phase. Thesethree scores were estimated using responses on the originallong questionnaire as a surrogate for responses on the finalquestionnaire. All items within a domain were scored iden-tically and weighted equally. Scores were calculated bysumming individual responses on items within each domain.Domain scores were adjusted to a scale of 0 to 100 with 100being the highest quality of life and 0 being the lowest or thegreatest possible effect on quality of life.Cumulative distribution graphs and descriptive statistics

for women with different comorbidities and within the threebasic groups were examined to determine how well theentire scores distinguished the groups. To benchmark thevalue of the OPTQoL in population quality of life studies,the relationships between OPTQoL domain scores and rel-evant domain scores of the SF-36 were compared usingSpearman’s correlation coefficient.

RESULTS

Focus groups

Thirteen focus groups from four geographical sites wereattended by 108 women with clinical osteoporosis definedas a history of fractures and/or significant loss of height orkyphosis. Five additional groups were of peri- or postmeno-pausal women without fractures or significant height lossbut who were known to have low BMD or who were con-cerned about developing clinical manifestations of osteopo-rosis because of family history, medications, or some otherreason (n 5 53). Another three groups were of healthcareprofessionals (n 5 26): one of family physicians, one ofendocrinologists and internists, and one of physical thera-

458 LYDICK ET AL.

pists. The last five groups were of spouses and/or othercaregivers of women with osteoporosis (n 5 19).

Item generation

The focus groups yielded 300 items that the workinggroup considered to be distinct. For convenience only, allitems were categorized into one of the following: activities,physical changes, symptoms, requirements for aids, adapta-tions, fears, pain, emotional symptoms, and attitudes. Thisorganization facilitated the development and administra-tion of the lengthy questionnaire. In addition to descriptionof specific tasks made difficult by osteoporosis and conse-quent adaptations, many women expressed feelings of dis-satisfaction with health care professionals regarding theunderstanding, education, treatment, and communicationavailable for osteoporosis. They felt that they received con-tradictory and inadequate information about osteoporosis.While a common topic within the focus groups, these com-plaints did not lend themselves to further study as itemsrelated to quality of life and were not included as potentialitems.

Study cohort—Item reduction

Four hundred and sixty-five women recruited from fivecenters took part in the phase of item reduction. The meanage of women participating was 68 (range 34–91). Over90% of the women lived in their own homes; the remainingwomen lived with family or friends, in a senior citizen orretirement home, or a nursing home. About 72% of thewomen were Caucasian and 24% were Asian (mostly fromthe Hawaii center). Demographic characteristics are shownin Table 1. Because several of the participating centers hadactive research programs in osteoporosis, 67% of thewomen participating had at least one bone density measure-ment. The proportion of women from each site with knownlevels of bone density ranged from all (Hawaii) to none(Rochester and Portland).The age distributions of enrolled women are shown in

Table 2. As would be expected, women with clinical osteo-porosis tended to be older and women who had neitherclinical osteoporosis nor low BMD tended to be somewhatyounger. The sum of all women by clinical category isgreater than 465 because women may have more than onecomorbidity. Only the categories, “clinical osteoporosis,”“low BMD,” and “all others” were defined to be mutuallyexclusive.

Item reduction

The final questionnaire had 26 scored questions relatingto quality of life in three domains—physical activity, socialfunction and fears—and six questions relating to osteopo-rotic changes and diagnosis of osteoporosis. In addition, weincluded two questions on overall health and one questioneach on age and race. See appendix for complete questionnaire.Seven items ask about physical difficulty women have

with specific tasks and are scored from “cannot do any-more” to “none.” A lower domain score means greaterdifficulty and worse quality of life. Ten statements about

adaptations women may have made in their life are scoredfrom “strongly agree” to “strongly disagree.” A lower do-main score indicates greater adaptations are required withan implied lower quality of life. The final section asks sixquestions about how much specific fears affect the woman’slife. Questions in this section are scored from “a lot” to“none.” A lower domain score indicates greater effect onlife due to fears, implying a lower quality of life.

Performance characteristics of items selectedfor final questionnaire

Cumulative distributions for all three groups, for each ofthe three OPTQoL domains, are shown in Figs. 1–3. Un-adjusted domain scores for women with clinical osteoporo-sis and each of the other four comorbidities considered areshown in Table 3. Women with depression consistently re-ported poorer scores for all domains. There was only modestseparation between scores for women with osteoporosis, ar-thritis, and other forms of mobility impairment, indicating thenonspecific nature of the effects of any of the age-relatedchronic diseases.Whereas 48% of the 465 women participating in the item

reduction phase had clinical osteoporosis, of the 90 womenwho scored 40 or less on the physical function domain of theOPTQoL, 63% had clinical osteoporosis (Fig. 1). Of the 161women with scores of 40 or lower on adaptations, 67% hadclinical osteoporosis (Fig. 2). Since the women who partic-ipated in this study were chosen to fulfill predeterminedqualifications, their numbers are not representative ofwomen in the general population.Age-adjusted means for each of the basic groups are

shown in Table 4. Scores are adjusted for age and mobilityimpairment, depression, cancer, and arthritis. Means shownrepresent a woman of age 65 who reports mobility impair-ment and no cancer, arthritis, or depression as measured by

TABLE 1. DEMOGRAPHIC CHARACTERISTICS OF THE 465 WOMEN

PARTICIPATING IN THE ITEM REDUCTION PHASE

Characteristic n (%)

RaceCaucasian 332 (72%)Asian 110 (24%)other 20 (4%)

Marital statusmarried 263 (57%)widowed 141 (30%)divorced/separated/nevermarried

59 (13%)

Educationcollege 193 (42%)high school 197 (43%)grade school 69 (15%)

Self-rated healthexcellent 39 (8%)very good 149 (32%)good 187 (40%)fair or poor 89 (19%)

QUALITY OF LIFE QUESTIONNAIRE FOR OSTEOPOROSIS 459

the CES-D. There were significant and substantial differ-ences among clinical osteoporosis and the other groups forthe two domains of physical functioning and adaptations.For fears (for example, fear of falling and having a frac-ture), there was less difference between women with clinicalosteoporosis and women who knew they had low bonedensity. Scores for all three OPTQoL domains were signif-icantly, but not greatly, correlated. Correlation coefficientsbetween domain scores were 0.31–0.38.

In addition, all three OPTQoL domain scores correlatedsignificantly with all domains of the SF-36 (Table 5). Thephysical OPTQoL domain and the physical functioning androle functioning physical domains of the SF-36 correlated

TABLE 2. AGE DISTRIBUTION AND COMORBIDITIES OF WOMEN PARTICIPATING IN ITEMREDUCTION PHASE

Category n

Percent of total

Age ,40 Age 40–54 Age 55–69 Age 70–84 Age $85

All 465 1 13 27 57 2Clinical osteoporosis 222 1 4 17 75 3Low BMD 101 1 12 26 58 3All others 142 1 18 55 27 0Arthritis* 176 0 14 29 56 2Mobility impairment* 123 1 15 37 46 2Depression* 63 3 8 33 52 3Cancer* 56 0 2 32 64 2None of above† 94 1 23 32 44 0

*These categories are not mutually exclusive with each other or with clinical osteoporosis category.†Low BMD alone not considered a comorbidity; some women in this group could have been told

they were at risk for osteoporosis.

FIG. 1. Cumulative distribution of OPTQoL physical ac-tivity domain score by group.

FIG. 2. Cumulative distribution of OPTQoL adaptationsdomain score by group.

FIG. 3. Cumulative distribution of OPTQoL fears domainscore by group.

TABLE 3. UNADJUSTED MEAN SCORES FOR OPTQOL DOMAINSWOMEN WITH SPECIFIED COMORBIDITIES

Clinical condition

Mean and standard deviation forOPTQoL domain

Physical Adaptations Fears

Clinical osteoporosis 60 6 24 44 6 15 49 6 13Low BMD 64 6 25 50 6 15 49 6 12All others 74 6 23 51 6 13 51 6 8Cancer* 72 6 25 50 6 15 51 6 9Depression* 49 6 26 43 6 13 42 6 11Arthritis* 60 6 24 48 6 14 49 6 11Other mobilityimpairments*

57 6 26 49 6 16 48 6 11

Lower score indicates greater impact or lower quality of life.*Without clinical osteoporosis.

460 LYDICK ET AL.

very highly. The other two OPTQoL domains—adaptationsand fears—show a relationship to decreased quality of lifeas measured by domains of the SF-36 but in addition aremeasuring attributes other than those captured by theSF-36.

DISCUSSION

Quality of life instruments can be evaluative, discrimina-tive, or predictive.(5,10) Our goal was to develop a discrim-inative questionnaire that would differentiate between peo-ple who have a better health-related quality of life andthose who have a worse health-related quality of life; fur-thermore, we wished to focus on those items most affectedby osteoporosis. Thus, we hoped to achieve a survey ques-tionnaire that would, as much as possible, be targeted toproblems associated with osteoporosis and that the majorityof women reporting greater disability and necessary adap-tations would do so because of osteoporosis rather thanother chronic conditions. For osteoporosis we chose a fairlystringent definition, one in which the consequences of boneloss are already manifest; that is, women with a history oflimb or rib fractures or multiple vertebral fractures suffi-cient to cause significant kyphosis or height loss.The comorbidities chosen for comparison with osteopo-

rosis were chosen because the effects of these conditionscould confound or obscure expressed feelings and attitudes

of the individual, whether for physical or other reasons.Osteoarthritis is a common age-related disorder leading topain and decreased mobility. Decreased mobility can occurfor a number of reasons besides osteoporosis or arthritis.Therefore, we included a second category of “mobility im-pairment” due to any cause. Depression has a strong effecton all realms of an individual’s quality of life.(11) Finally,cancer has a profound impact on quality of life because ofthe effects of the illness, the treatment, and fears of im-pending death.Because no gold standard exists for an osteoporosis-

targeted quality of life questionnaire, validation strategiesconsisted of content, face, and construct validity. Contentvalidity examines the extent to which the instrument iscomprehensive.(10) That criterion was met by the extensiveefforts to obtain and include items described by individualswith osteoporosis. These efforts included not only 26 focusgroups among over 200 women with osteoporosis and care-givers, but an item reduction phase that systematicallyasked 465 additional women about the impact of specificitems on their lives.Face validity examines whether an instrument appears to

be measuring what it is intended to measure. There is animpreciseness to both the definition of osteoporosis and thedefinition of quality of life. Osteoporosis is a chronic dis-ease just now becoming recognized as a pathological con-dition rather than a normal consequence of aging. Theproblems with definition and estimation of quality of lifeare legendary.(12) But wherever possible, we benchmarkedevery item against the available measures of osteoporosis—fractures, loss of height, kyphosis, and low bone density—and against a standard accepted survey measure of qualityof life, the SF-36.(8) There is general, although imperfect,agreement that the following domains should be consideredin assessing health-related quality of life(13): performance ofsocial roles, physical functioning, emotional status, cogni-tive functioning, and sense of well-being. Additional do-mains have been proposed such as sleep, energy and vitality,health perceptions, and symptoms.(14) The SF-36 lacks aspecific domain for sleep. It is possible that we could havemissed some items in using the SF-36 as our quality of lifebenchmark. However, this lack of sensitivity is probablymore theoretical than real since most domains are posi-tively and significantly correlated,(15) all presumably con-tributing to the total underlying construct believed to behealth-related quality of life.Construct validity involves comparison between mea-

sures and examines the logical relations that should existbetween a measure and characteristics of patients and pa-tient groups. A good instrument should distinguish betweengroups with and without the disease. It should also distin-guish between groups with and without the disease-relatedimpact on symptoms, function, health status, and emotionalcorrelates. Those patients with a greater number and sever-ity of symptoms should have lower functional scores on agood quality of life instrument. For physical and socialfunctioning domains, women with clinical osteoporosis didindeed have the worst scores. Women with low bone densitytended to score between women with clinical osteoporosisand all others on the physical functioning domain, but

TABLE 4. ADJUSTED* MEAN SCORES FOR OPTQOL DOMAINSFOR ALL WOMEN PARTICIPATING IN ITEM REDUCTION PHASE

OPTQoL domain

Mean and standard deviation

Clinicalosteoporosis

LowBMD All others

Physical activities 496 27 60 6 29 74 6 24Adaptations 44 6 17 54 6 9 49 6 14Fears 49 6 17 50 6 14 52 6 10

*Scores adjusted for age of 65, presence of mobility impairment,and absence of depression, cancer, and arthritis.

TABLE 5. CORRELATIONS BETWEEN OPTQOL DOMAINS ANDSF-36 DOMAINS

SF-36 Domain

OPTQoL domain

Physical Adaptations Fears

Physical 0.71 0.40 0.32Social 0.48 0.34 0.35Role-physical 0.61 0.36 0.30Role-emotional 0.38 0.31 0.26Mental health 0.35 0.23 0.34Vitality/fatigue 0.55 0.29 0.33Bodily pain 0.56 0.24 0.32General health 0.58 0.43 0.32

Values are Pearson correlation coefficients; all are significant atp , 0.0001.

QUALITY OF LIFE QUESTIONNAIRE FOR OSTEOPOROSIS 461

slightly better than women without any indications of os-teoporosis on domain referring to social adaptations.No consistent relationship was seen for the fear domain.

Rubin and Cummings(9) have previously reported thatwomen told their bone density was below normal becamemore worried about fractures, were more fearful of falling,and limited their daily activities to avoid falling. The liter-ature on coping and adjustment(16) has suggested that oftenthe greatest fears of disease consequences are not amongthose with the greatest severity of disease.Ideally, we would be able to ask the question, “How much

does your osteoporosis affect your ability to perform acertain task?” This is the standard form for disease-specificquestionnaires.(17) Because this questionnaire will be usedin a survey of the general population, not all women willhave osteoporosis or be aware of it if they do. The fearsdomain is the only area in which we could refer to thedisease in question and/or the sequelae of fractures. Withinthis domain, we chose to rely on the strong face validity ofthe items rather than select only those items chosen moreoften by women with clinical osteoporosis.Finally, for a discriminative instrument, we need to assess

reliability.(10) Ideally the variability in scores between indi-viduals should be much greater than the variability withinindividuals. Test-retest administration of the OPTQoL iscurrently under way; at the present time no information isavailable on the reliability of our instrument. In addition,on-going efforts will examine the coherence and internalconsistency of the items included in the domains. Finally,examing the performance characteristics in a new cohortwill permit greater understanding of OPTQoL scores withrespect to the general population.Generally, researchers considering the impact of osteo-

porosis on quality of life have focused on the painful frac-tures. Likewise, osteoporosis-targeted questionnaires onquality of life developed to date have concentrated on theshort-term effects of painful vertebral fractures.(18–22) Ge-neric quality of life questionnaires can be used when thedisease has had a major effect on functional status, forexample after hip fracture(23–25) or severe vertebral defor-mity.(26,27) These measures do not contribute much to theunderstanding of the total impact of osteoporosis in thegeneral population. Generic instruments have limited abil-ity to cover all aspects of a given disease. For precisely thisreason, disease-targeted quality of life measures have be-come necessary to quantify the discomfort, disability, anddependence that affect patients at different life states.(4)

Targeted questionnaires do not always provide an advan-tage over generic instruments.(28) In this case, the physicalfunctioning domains of the SF-36 may be just as effective indemonstrating the impact of osteoporosis on this area offunctioning as the physical domain of the OPTQoL. How-ever, the domains on adaptations and fears clearly add tothe information that can be obtained from the SF-36.No previous studies have tried to investigate all effects of

osteoporosis on the population, such as fears, adaptationsbecause of physical changes and limitations, and concernsabout selfimage. We describe the development and valida-tion of an osteoporosis-targeted instrument that may pro-vide researchers with an aid to better understand the nat-ural history of osteoporosis, provide more comprehensive

information on the impact of osteoporosis, and better targetdisease prevention or intervention therapies.

ACKNOWLEDGMENTS

We acknowledge the time-consuming and dedicatedwork of our interviewers and moderators: Kristen Freeman(Hawaii Osteoporosis Center), Linda Herskovitz (WayneState University), Marge Kurland (Olmsted MedicalGroup), Roberta Mansfield (Providence Medical Center),and Melissa Reuland (University of Maryland at Baltimore).We relied extensively on their input during the initial expres-sion of items and, during the second phase, on their judgmentof which questions “worked.” We also thank Ed Parmeleefor his excellent help in coordinating the early phases of thiseffort and Drs. Jeffrey Dwyer and Jay Magaziner for theirknowledge and experience. Most of all, we thank the manywomen who participated and gave freely of their time inorder to share their experiences and feelings with us.

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Address reprint requests to:Eva Lydick

Department of ResearchOlmsted Medical Center

210 9th Street, SERochester, MN 55903 U.S.A.

Received in original form June 24, 1996; in revised form September26, 1996; accepted October 14, 1996.

APPENDIX—FINAL QUESTIONNAIRE

Section 1: Physical Function (7 items). Responses: None; alittle; a moderate amount; a lotHow much physical difficulty do you have pushing or pulling

heavy doors?How much physical difficulty do you have vacuuming?How much physical difficulty do you have lifting something

heavy, for example a shopping bag or small child?How much difficulty do you have with leisure time activities,

such as walking, swimming, bowling, golfing?How much physical difficulty do you have shopping for clothes

or presents?How much physical difficulty do you have preparing meals for

special gatherings of family or friends?How much physical difficulty do you have visiting relatives or

friends who do not live close by?Section 2: Adaptations (9 Items). Responses: Strongly agree;

agree; disagree; strongly disagreeI need to carefully plan activities so I will not become exhausted.I avoid travel because it’s too much trouble or too tiring.I have to avoid activities with a group because I can only do

things at my own speed.My physical health keeps me from doing community service or

other volunteer work.It is difficult to plan activities even a few days in advance because

I never know what my physical health will be like.I wear clothes I consider less attractive because that’s all that fits.I wear practical shoes for safety.I use items, for example reachers and grabbers, to assist me

when I reach for things.It is difficult for me to reach up or down so I keep items more

or less at eye level.Section 3: Fears (6 Items). Responses: No, not at all; A little; A

moderate amount; A lot

Does the fear of falling unless holding on to something affectyour life?Does the fear of falling and not being able to get up affect your

life?Does the fear of falling and having a fracture (broken bone)

affect your life?Does the fear of pain from fractures affect your life?Does the fear of future physical limitations due to osteoporosis

affect your life?Does the fear of osteoporosis because of lack of help affect your

life?Section 4: Osteoporotic Changes (3 Items).Have you lost height since the age of 25? If yes, how many inches

have you lost?Have you noticed a change in your posture, such as a round

back? If no, how important is it for you to avoid developing thischange in your posture? If yes, how important is it for you to hidethis change in your posture?Have you had a hip, wrist, or spine fracture since age 45? If yes,

were any of these fractures the result of a sudden move or a fallfrom a standing height or less (such as slipping, stumbling, orfalling from bed)?Section 5: Health and Demographics (7 Items).How would you rate your overall health?How would you rate your quality of life as regards your health?Has anyone in your family (mother, sister, grandmother, aunt)

or close friends/relatives had osteoporosis?Have you ever had your bone density (a test for osteoporosis)

measured?Have you ever been told by a doctor that you had osteoporosis?How old are you?With which ethnic group do you most associate yourself?

QUALITY OF LIFE QUESTIONNAIRE FOR OSTEOPOROSIS 463