characteristics of inner-city children with asthma: the national cooperative inner-city asthma study
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Characteristics of Inner-City Children With Asthma:The National Cooperative Inner-City Asthma Study
Meyer Kattan, MD,1 Herman Mitchell, PhD,2 Peyton Eggleston, MD,3Peter Gergen, MD, MPH,4 Ellen Crain, MD, PhD,5 Susan Redline, MD,6
Kevin Weiss, MD,7 Richard Evans III, MD, MPH,8 Richard Kaslow, MD,9Carolyn Kercsmar, MD,6 Fred Leickly, MD,10 Floyd Malveaux, MD, PhD,11
and H. James Wedner, MD12
Summary. Asthma morbidity has increased dramatically in the past decade, especially amongpoor and minority children in the inner cities. The National Cooperative Inner-City Asthma Study(NCICAS) is a multicenter study designed to determine factors that contribute to asthma mor-bidity in children in the inner cities. A total of 1,528 children with asthma, ages 4 to 9 years old,were enrolled in a broad-based epidemiologic investigation of factors which were thought to berelated to asthma morbidity. Baseline assessment included morbidity, allergy evaluation, adher-ence and access to care, home visits, and pulmonary function. Interval assessments wereconducted at 3, 6, and 9 months after the baseline evaluations.
Over the one-year period, 83% of the children had no hospitalizations and 3.6% had two ormore. The children averaged 3 to 3.5 days of wheeze for each of the four two-week recallperiods. The pattern of skin test sensitivity differed from other populations in that positive reac-tions to cockroach were higher (35%) and positive reactions to house dust mite were lower(31%). Caretakers reported smoking in 39% of households of children with asthma, and cotinine/creatinine ratios exceeded 30 ng/mg in 48% of the sample. High exposure (>40 ppb) to nitrogendioxide was found in 24% of homes. Although the majority of children had insurance coverage,53% of study participants found it difficult to get follow-up asthma care. The data demonstratethat symptoms are frequent but do not result in hospitalization in the majority of children. Thesedata indicate a number of areas which are potential contributors to the asthma morbidity in thispopulation, such as environmental factors, lack of access to care, and adherence to treatment.Interventions to reduce asthma morbidity are more likely to be successful if they address themany different asthma risks found in the inner cities. Pediatr. Pulmonol. 1997;24:253262. 1997 Wiley-Liss, Inc.
Key words: asthma; children; inner-city.
1Mount Sinai School of Medicine, New York, New York.
2New England Research Institutes, Watertown, Massachusetts.
3Johns Hopkins School of Medicine, Baltimore, Maryland.
4National Institute of Allergy and Infectious Disease (National Insti-tutes of Health, Bethesda, Maryland).5Albert Einstein College of Medicine, Bronx, New York.
6Case Western Reserve University, Cleveland, Ohio.
7National Institute of Allergy and Infectious Disease (National Insti-tutes of Health, Bethesda, Maryland) (now at Center for Health Ser-vices Research, Rush Primary Care Institute, Chicago, Illinois).8Childrens Memorial Hospital, Chicago, Illinois.
9University of Alabama, Birmingham, Alabama.
10Henry Ford Hospital, Detroit, Michigan.
11Howard University College of Medicine, Washington, DC.
12Washington University School of Medicine, St. Louis, Missouri.
Contract grant sponsor: National Institute of Allergy and InfectiousDisease (National Institutes of Health, Bethesda, MD); Contract grantnumbers: UO1 A1-30751, A1-30752, A1-30756, A1-30772, A1-30773-01, A1-30777, A1-30779, A1-30780, and N01 A1-15105.
Correspondence to: Ernestine Smartt, RN, DAIT, NIAID, NIH, SolarBuilding, Room 4A42, 6003 Executive Boulevard, Bethesda, MD20892-7640.
Received 23 April 1996; accepted 30 June 1997.
Pediatric Pulmonology 24:253262 (1997)
1997 Wiley-Liss, Inc.
The morbidity and mortality associated with asthmahave increased in recent years. During the decade from1982 to 1991, mortality due to asthma has increased 42%among 534-year-olds.1 Weitzman et al., found a 39%increase in the prevalence of active asthma among chil-dren under 18 years of age.2 This increase is even moredramatic among the very young, under age 5.3 Poor andminority urban areas contribute disproportionately to thisincreasing asthma morbidity and mortality.46 The ma-jority of these studies of increased asthma morbidityhave focused on hospitalization or emergency depart-ment (ED) visits taken from large national utilizationdatabases.3,4,79 A number of other studies have mea-sured symptom incidence in samples of asthmatics, usu-ally at a single point in time.10 Those studies have fo-cused on factors which may be related to this increasedmorbidity and have typically focused on the relationshipof one, or possibly two factors and their impact on hos-pitalizations and ED use. The first phase of the NationalCooperative Inner-City Asthma Study (NCICAS) wasspecifically designed to capture extensive utilization andsymptom data on a large sample of inner-city children,with repeated measures of utilizations and symptomsover an extended period of time. This report provides adetailed description of utilization and asthma symptomsover a one-year period, the environmental milieu, andaccess to care in a geographically diverse inner-citypopulation of children with mild to severe asthma. Thepsychosocial characteristics of this cohort are publishedelsewhere.11 Subsequent analyses will allow us to relatespecific factors to morbidity among inner-city asthmaticsand provide the basis for an intervention.
In the NCICAS project, 1,528 children with asthma,ages 4 through 9, and their caretakers were given anextensive baseline assessment including demographiccharacteristics, health history, medicine use, access tocare, adherence to treatment, environmental factors, psy-chological assessments, as well as symptoms and healthcare utilization. The full design and methodology
of NCICAS is detailed in accompanying articles pub-lished in this journal issue.11,12 Children were recruitedfrom EDs and clinics in inner-city areas based on phy-sician-diagnosed asthma and presence of asthma symp-toms for more than 3 days in the previous 12 months, orcough, wheezing, or shortness of breath that lasted morethan 6 weeks in the previous 12 months. This recruitmentprocedure yielded a sample in which 9.5% of the childrenhad not been diagnosed with asthma but were recruitedbased on asthma symptoms.
Skin-prick allergy tests, pulmonary function, and urinecollection for cotinine were done. Home visits were con-ducted to gather dust samples for roach, dust mite, andcat allergens in a large subsample of the families. Duringthis home visit, the environment was assessed and thecollection of nitrogen dioxide (NO2) specimens was ini-tiated. Following this baseline assessment, telephone as-sessments of symptoms and utilization were conducted at3-, 6-, and 9-month intervals. Recall over the prior 3months for utilization (hospitalizations, ED visits, andunscheduled physician visits) was assesed at baseline andat each 3-month follow-up telephone call, providing afull year of utilization information for the sample. Ateach of these four measurement periods, a 2-week recallof symptoms was obtained (loss of sleep, slow-down ofplay, and wheeze).
Home visits were conducted on 663 (43.4%) of studysubjects between November and July. Using a checklist,information was recorded both from direct inspection(such as general repair, carpeting, mattress covers, evi-dence of infestation, and of smoking in the home) orfrom questions to the family (such as laundry arrange-ments, pets, or infestations).Skin Tests
Skin testing was performed by the prick puncturemethod on the volar surface of the forearm using a Mul-titestert device.13 Allergen extracts (D. pteronyssinus, D.farinae, cat pelt, dog pelt, rat pelt, mouse pelt, Germanand American cockroach mixture, Alternaria tenuis,Penicillium, mixed grasses, orchard grass, white oak,maple, and giant and short ragweed) were obtained inglycerosaline (Greer Laboratories, Lenoir, NC). All ex-tracts were 1:20 weight/volume except mites, which were10,000 Allergy Units (AU) per ml. Resulting whealswere outlined in ink 15 minutes after puncture and theoutline transferred to tape. A test was considered valid ifthe negative control wheal was at least 1 mm smaller thanthe positive histamine wheal. A test for any given antigenwas considered positive if its value exceeded the nega-tive wheal by at least 2 mm.
SmokingUrine samples were collected from children at the time
of the baseline interview, then transferred to capped plas-
AU Allergy UnitsBTPS Body temperature and barometric pressure, saturatedCCR Cotinine/creatine ratioED Emergency DepartmentETS Environmental tobacco smokeFEV1 Forced expiratory volume in one secondFVC Forced vital capacityNCICAS National Cooperative Inner-City Asthma StudyNO2 Nitrogen dioxide
254 Kattan et al.
tic tubes, frozen, and shipped in dry ice to a centrallaboratory at Henry Ford Hospital. Samples were ana-lyzed for cotinine content with an ELISA method usinga polyclonal antibody (Cotitraqt; Serex, Englewood,NJ).14 Urinary creatinine was assayed by the clinicalchemistry laboratory at Henry Ford Hospital and resultswere reported as continine/creatinine ratio (ng/mg).
Nitrogen DioxideQuestions potentially relevant to NO2 exposure were
asked during the baseline interview and confirmed dur-ing the home visit. At the time of the home visit a Palmestube was taped to a wall in the childs sleeping area. Thefamily was instructed to seal and mail them back to theasthma study center after 7 days. The tube was shipped toa central laboratory for analysis. The samplers have asensitivity of 600 ppb-hr, so that over 7 days a concen-tration above 3.6 ppb could be detected and samplesdiffering by th