Tuberculosis re-treatment outcomes within the public service in Nairobi, Kenya

Objectives: This study was undertaken to describe treatment outcomes in patients started on a re-treatment drug regimen, assess the quality of follow up procedures and the adequacy of the currently advocated re-treatment drug regimen in Nairobi, Kenya. Design: A retrospective study. Setting: Mbagathi District Hospital (MDH), Nairobi, a public hospital that serves as the Tuberculosis (Tb) referral centre for Nairobi. Materials and methods: The Tb register at the MDH was used to identify patients who were on the re-treatment regimen for Tb. Case records for these patients were then retrieved. From these sources, information on age, sex, HIV status, previous and current tuberculosis disease and drug regimens, adherence to treatment and treatment outcomes, was obtained. Descriptive statistics was used to analyse the data. Results: Of the total of 4702 patients registered at the MDH between 1996 and 1997, 593 (12.6%) were patients with either recurrent Tb, returning to treatment after default or had failed initial treatment. Of the 593 patients, case records were unavailable for 168 and 17 were children below the age of ten in whom the diagnosis of Tb was uncertain making a total of 185 patients who were excluded from the study. Of the remaining 408 patients, 77 (18.9%) were cured, 61 (15.0%) completed treatment without confirmation of cure, two (0.5%) defaulted, six (1.5%) died and 262 (64.2%) had no outcome information. There were no treatment failures. Treatment success defined as cure or treatment completion was achieved in 94.5% of the 146 patients in whom outcome data were available. HIV positive patients had a statistically significant poorer success rate (34/40, 85%) when compared with HIV negative patients (104/106, 94%), p=0.004. Mycobacterium tuberculosis culture and drug susceptibility testing, was not done. Conclusion: The high number of patients with no treatment outcome information at the MDH is worrying, as these patients may harbour drug resistant bacilli and reflects an inadequate follow up service for Tb re-treatment in Nairobi. However, where treatment outcomes could be assessed, the currently advocated re-treatment regimen achieved a high success rate. These observations point to an urgent need to improve Tb documentation and follow up procedures within the public service in Nairobi in order to forestall the emergence and spread of drug resistant Tb. (East African Medical Journal: 2002 79(1): 11-15

Cost-effectiveness of polymerase chain reaction versus Ziehl-Neelsen smear microscopy for diagnosis of tuberculosis in Kenya

Laboratory services, particularly in large sub-Saharan cities, are overstretched, and it is becoming difficult both for patients and health staff to adhere to the diagnostic procedures for tuberculosis. Alternative techniques would be welcome. The polymerase chain reaction (PCR) has the potential to be cost-effective. We compared the cost-effectiveness of two diagnostic strategies, Ziehl-Neelsen (ZN) on three specimens followed by chest X-ray (CXR), and AMPLICOR MTB PCR on the first specimen only. Three sputum samples were collected from tuberculosis (TB) suspects attending the Rhodes Chest Clinic, Nairobi. All samples were subjected to ZN, PCR and Löwenstein-Jensen culture used as gold standard. CXR was used to diagnose smear-negative TB. Cost analysis included health service and patient costs. Costs per correctly diagnosed case were US dollar 41 and dollar 67 for ZN and PCR, respectively. When treatment costs were included, including treatment of culture-negative cases, PCR was more cost-effective: dollar 382 vs. dollar 412. PCR may be an alternative in settings with many patients. PCR is patient friendly, CXR is not necessary and, unlike ZN, its performance is hardly affected by the human immunodeficiency virus. PCR can handle large numbers of specimens, with results becoming available on the same da

Cost-effectiveness of the polymerase chain reaction versus smear examination for the diagnosis of tuberculosis in Kenya: a theoretical model

A major out-patient tuberculosis clinic in Nairobi, Kenya. To ascertain the cost-effectiveness of the polymerase chain reaction (PCR) for the diagnosis of tuberculosis in an urban setting in a developing country. A cost-effectiveness analysis of PCR and direct smear microscopy examination based on theoretical modelling. The cost-effectiveness was expressed in costs per correctly diagnosed tuberculosis patient for each of the two diagnostic techniques. Data were obtained from the literature, from the staff and the register at the health facility and from structured interviews with patients. Assumptions were made when no data were available. The PCR is expected to be more specific and sensitive than the routine procedure for diagnosis, but it is also more costly. The routine procedure based on direct smear microscopy turned out to be 1.8 times as cost-effective as PCR. It is concluded that the PCR method can potentially be a cost-effective screening procedure for tuberculosis, provided that the largest contributing cost component, the costs of the PCR-kit, can be reduced substantiall

HIV sero-prevalence among tuberculosis patients in Kenya

Objective: To determine HIV seroprevalence among tuberculosis patients and the burden of HlV attributable tuberculosis among notified patients in Kenya.Design: A cross-sectional anonymous unlinked HlV seroprevalence survey.Setting: Tuberculosis diagnostic clinics of the National Leprosy Tuberculosis Programme in 19 districts.Subjects: One thousand nine hundred and fifty two newly notified tuberculosis patients.Interventions: Selection and registration of eligible subjects followed by obtaining 5ml of full blood for haemoglobin testing and separation of serum for HIV testing by ELISA.Main outcome measures: HlV seroprevalence per district and burden of HIV attributable tuberculosis among tuberculosis patients.Results: A total of 1,952 eligible patients were ended. The weighted seroprevalence in the sample was 40.7% (range 11.8-79.6% per district). The seroprevalence was significantly higher among females and patients with sputum-smear negative tuberculosis. Chronic diarrhoea, female sex, oral thrush and a negative sputum were independent risk factors for HIV infection. The Odds ratio for HIV infection in female tuberculosis patients aged 15-44 years, was 5.6 (95% CI 4.5-6.9) compared with ante-natal clinic attenders. The population attributable risk was 0.22 in 1994.Conclusion: The HlV epidemic has had a profound impact on the tuberculosis epidemic in Kenya and explains about 41% of the 94.5% increase of registered patients in the period 1990-1994 and 20% of all registered patients in 1994. Repetition of the survey with inclusion of a more representative control group from the general population may provide a more accurate estimation of the burden of HIV attributable tuberculosis

Tuberculosis and the HIV epidemic: increasing annual risk of tuberculous infection in Kenya, 1986-1996.

OBJECTIVES: The purpose of this study was to assess the impact of the increased incidence of tuberculosis (TB) due to HIV infection on the risk of TB infection in schoolchildren. METHODS: Tuberculin surveys were carried out in randomly selected primary schools in 12 districts in Kenya during 1986 through 1990 and 1994 through 1996. Districts were grouped according to the year in which TB notification rates started to increase. HIV prevalence in TB patients and changes in TB infection prevalence were compared between districts. RESULTS: Tuberculous infection prevalence rates increased strongly in districts where TB notification rates had increased before 1994 (odds ratio = 3.1, 95% confidence interval = 2.3, 4.1) but did not increase in districts where notification rates had increased more recently or not at all. HIV prevalence rates in TB patients were 50% in districts with an early increase in notification rates and 28% in the other study districts. CONCLUSIONS: Countries with an increasing prevalence of HIV infection will need additional resources for TB control, not only for current patients but also for the patients in additional cases arising from the increased risk of TB infection

A comprehensive comparison of Ziehl-Neelsen and fluorescence microscopy for the diagnosis of tuberculosis in a resource-poor urban setting

Nairobi City Council Chest Clinic, Kenya. To establish the efficiency, costs and cost-effectiveness of six diagnostic strategies using Ziehl-Neelsen (ZN) and fluorescence microscopy (FM). A cross-sectional study of 1398 TB suspects attending a specialised chest clinic in Nairobi subjected to three sputum examinations by ZN and FM. Lowenstein-Jensen culture was used as the gold standard. Cost analysis included health service and patient costs. Of 1398 suspects enrolled, 993 (71%) had a complete diagnostic work-up involving three sputum specimens for ZN and FM, culture and chest X-ray (CXR). Irrespective of whether ZN or FM was used on one, two or three smears, the overall diagnostic process detected 92% culture-positive cases. Different strategies affected the ratio of smear-positive to smear-negative TB; however, FM was more sensitive than ZN (P <0.001). FM performance was not affected by the patient's HIV status. The cost per correctly diagnosed smear-positive case, including savings, was 40.30 US dollars for FM on two specimens compared to 57.70 US dollars for ZN on three specimens. The FM method used on one or two specimens is more cost-effective and shortens the diagnostic process. Consequently, more patients can be put on a regimen for smear-positive TB, contributing to improved treatment and reducing transmissio