editorial: tuberculosis control: did the programme fail or did we fail the programme?

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  • Tropical Medicine and International Health

    volume 2 no 8 pp 715718 august 1997

    1997 Blackwell Science Ltd715

    Editorial: Tuberculosis control: did the programme fail or didwe fail the programme?

    Introduction

    Under pressure of the increasing numbers of tuberculosis(TB) cases in the world, TB control has once againbecome a major challenge. As such it is the subject ofintensive scientific activity, as evidenced by the numerousstudies and publications that have been devoted to it overthe last few years. The Lancet recently published twodocuments which summarize present concerns: theminutes of the conference organized in Washington DCby The Lancet, in September 1995: The challenge oftuberculosis: statements on global control andprevention (Enarson et al. 1995) and an article whichproposes substantial modifications of activities in thestandard tuberculosis control programme (De Cock &Wilkinson 1995). From the most recent literature, twomajor challenges may be identified (Reichman &Hershfield 1993; Porter & McAdam 1994; De Cock &Wilkinson 1995; Enarson et al. 1995): On the one handthere is a call for the development of new diagnostictechniques, especially procedures that are faster andmore sensitive than smears or cultures and techniquesthat would improve or facilitate the diagnosis of smear-negative TB; and a call for new treatments that areeffective against multidrug-resistant TB and/or thatwould shorten length of treatment. On the other hand,the scientific community also acknowledges theimportance of some operational aspects of TB, such asproblems of drugs delivery and financing, and patientcompliance to treatment (Reichman & Hershfield 1993;Porter & McAdam 1994; De Cock & Wilkinson 1995;Enarson et al. 1995). This last point is considered a toppriority, and WHO is currently promoting DOT (DailyObserved Therapy) as a new strategy to be implementedby each TB control programme (Enarson et al. 1995).

    However, other aspects linked to the organizationand the functioning of health services, or linked to theperception of the illness by both health personnel andpatients, are underestimated. In his presidential address,given at the 21st Andhra Pradesh TB and Chest DiseasesConference held in July 1994 in India, Dr Ranga Rao

    proposed a critical self-evaluation of the state TBcontrol programme which started more than threedecades ago (Rao 1994). This physician, who has beenworking as a TB officer for more than 25 years,identified 17 major weaknesses of the TB controlprogramme. His very impressive list begins with:

    We failed in implementing the programme in thehealth districts.

    We failed in providing the services of all the trainedmedical and paramedical key personnel continu-ously in some districts, due to frequent transfers orotherwise.

    We failed in improving the laboratory services inthe primary health centres.

    We failed in seeking administrative support of thecompetent authorities to run the programme etc.

    What is striking about this presidential address given bya TB specialist to the members of a tuberculosisassociation, is that most of the 17 weaknesses identifiedare related to human or organizational failures andsome to lack of political will, but none are directlyattributed to a technical problem.

    Whether in industrialised or in low-resource countries,our experience points in the same direction: we failed inimplementing TB control programmes mainly foroperational reasons (human and/or organizational failureslinked to the overall functioning of health systems), notbecause of a problem of diagnostic tools or drugresistance. These operational reasons are due to specificchallenges arising from the integration of a TB controlprogramme into general health services and from thequality of the overall functioning of the health services.

    An operational model for the analysis of TB controlprogrammes

    Piot (1967), who at that time was attached to WHOsTB programme, put forward a model enabling a

  • Tropical Medicine and International Health volume 2 no 8 pp 715718 august 1997

    B. Dujardin et al. Tuberculosis Control

    1997 Blackwell Science Ltd716

    comprehensive assessment of all the different technicaland operational aspects of a TB control programme. Wepropose a simplified version of this model focusing onthe problems raised by the integration of the TBprogramme into the general health services.

    The model, which is conceptually simple, is based onthe passive detection strategy of smear-positive TBcases. It starts from a description of the different stepsindividuals in the community go through betweenbecoming ill with active TB and getting cured by the TBcontrol programme under consideration. The main steps the number of which may vary according to thecharacteristics of the control programme aresummarized below:

    Step 1: Motivation: Patients suffering from symptomsrelated to TB contact a health caredelivery point.

    Step 2: Selection: The health professional suspectsTB and requests a sputumexamination (smear).

    Step 3: Examination: The sputum test is correctlycarried out on the patients thusselected.

    Step 4: Sensitivity: The smear is positive if the patienthas bacilli in the sputum.

    Step 5: Prescription: The newly identified case of TBreceives the correct treatmentprescription.

    Step 6: Treatment: The TB patient obtains theprescribed treatment.

    Step 7: Regularity: The TB patient takes his treatmentregularly as prescribed.

    Step 8: Effectiveness: The patient is cured with a certainprobability if treatment is taken asprescribed.

    In ideal circumstances, all new cases of TB consultwithout delay, are suspected of suffering of TB and arediagnosed promptly and accurately, receive a correcttreatment prescription, obtain the prescribed treatmentand take the full treatment regimen regularly to finallybe cured. This would lead to a 100% prompt cure rateof new TB cases in the population and to a decrease inthe transmission of TB. Of course, real life is different.

    At each step problems and difficulties arise: a suspectindividual is not identified, there is no reagent to carryout the sputum smear, a positive sputum is missed bythe laboratory technician, drugs are out of stock, thepatient does not present at the health centre regularly,and so on The probability that a patient does proceedfrom one step to the next is a measure of theperformance of different TB control activities.

    Some steps are essentially technical (sensitivity ofdiagnostic test, theoretical effectiveness of treatment)and depend on the choice made at the central level bythe TB programme officers. Their probabilities aretheoretically independent of circumstances. Other stepsprobabilities are quite variable from one situation toanother because they depend in the first place on thequality and performance of the health services where TBcontrol activities are integrated. These so calledoperational steps depend on the operational quality ofthe health services such as they are and include:motivation, selection, examination, prescription,treatment and regularity. To illustrate the importance ofthe problems encountered in the field and the need of aglobal approach, we briefly discuss two of theseoperational steps, examination and regularity.

    Examination is often the weakest link in the chain ofsteps that should lead to the cure of TB patients. Manytypes of problems are encountered in practice. Firstthere is the case of the doctor who failed to properlyexplain the importance of this examination, and thepatient who thus is not inclined to queue up again at thelaboratory, especially if he needs to come back twomore times in order to complete the required series ofthree sputum examinations and one more time to hearthe result (the whole process often takes more than aweek, several days at best (Aluoch et al.1984). Secondly,the laboratory technician does not adequately instructthe patient on how to produce sputum or does not allowhim the necessary time; the collected specimen is salivainstead of bronchial secretions. We have seen thissituation over and over again. Thirdly, the sputumcollection may be correct, but the smear not correctlyprepared: old slides are used (one of the sources of falsepositives), the sputum is badly spread out, reagents areeither past the expiry date or out of stock, procedure isnot followed, the staining is done badly.

    Lastly, an adequate sputum sample is correctlyprepared, but microscopic examination by thelaboratory technician is not reliable due to

  • Tropical Medicine and International Health volume 2 no 8 pp 715718 august 1997

    B. Dujardin et al. Tuberculosis Control

    1997 Blackwell Science Ltd717

    incompetence or lack of professional attitude. Anotherexplanation our own experience in Latin America has to do with integration of TB programs. In theirwillingness to detect as soon as possible all new TBcases, TB officers tend to push health professionals toidentify more and more suspect patients (the sometimesobserved rule that 1% of the new patients at the OPDor curative clinic have to be selected for sputumexamination). As a consequence, too many suspectsmay be referred to the laboratory, the workloadbecomes too high, the health officer tends to select fewersuspected patients and/or the laboratory technician doesnot respect the prescribed duration of reading the slideand the result is a false negative. This is an examplewhere maximization could be counterproductive.

    The reliability of this step (quality of sputumproduction and collection, quality of smear preparation,quality of microscopic examination) thus appears to becrucial, all the more so since it depends entirely onfactors within the health services, and especially sincehigh quality (in other words, a probability value close to1.0) is tech