The influence of intravenous drug use and HIV infection in the transmission of tuberculosis.

OBJECTIVE: To investigate whether smear-positive pulmonary tuberculosis (TB) patients present a different risk of TB transmission according to their HIV status, in an area where the majority of HIV-infected patients studied were intravenous drug users (IVDU). METHODS: A case-control study was performed on smear-positive pulmonary TB patients diagnosed between 1990 and 1993 for whom a contact study had been performed. Patients with and without HIV infection were matched by age (+/- 3 years), sex and hospital of diagnosis. A micro-epidemic was defined if two or more secondary cases were detected from the same index case. Data were analysed comparing the percentage of contacts with TB in both groups. RESULTS: Thirty-six secondary cases were detected in 436 contacts of 124 HIV-infected TB patients, whereas only 24 were identified in 624 contacts of 124 HIV-seronegative TB patients [odds ratio (OR), 2.14; 95% confidence interval (CI), 1.22-3.77; P = 0.004]. Comparing the contacts of HIV-infected patients, 34 secondary cases of TB were detected in 371 contacts of 97 IVDU, whereas only two cases were detected in 85 contacts of 27 non-IVDU (OR, 4.19; 95% CI, 1.09-15.95). HIV-seropositive index cases were observed to cause more micro-epidemics than seronegative cases (eight versus four), indicating that micro-epidemic cases were more frequent in the contacts of HIV-infected subjects (27 out of 36 versus 10 out of 24; OR, 1.41; 95% CI, 1.41-12.49; P = 0.009). All index cases in eight micro-epidemics were HIV-seropositive IVDU, whereas only four micro-epidemics were generated by HIV-seronegative subjects, none of whom were IVDU. CONCLUSIONS: Smear-positive pulmonary TB patients were more likely to transmit TB if they were HIV-infected, as evidenced by the role of IVDU in generating micro-epidemics.

Current status of treatment completion and fatality among tuberculosis patients in Spain.

OBJECTIVES: To determine treatment completion among patients with tuberculosis (TB), and to analyse factors associated with treatment default and fatality. METHODS: A prospective cohort study of patients who began treatment between 1 June 1999 and 31 May 2000 in areas where members of the SEPAR Tuberculosis and Respiratory Infections Group work. Factors associated with treatment default and fatality were studied using logistic regression, calculating odds ratios (OR) and their 95% confidence intervals (95%CI). RESULTS: The study involved 142 physicians from 76 different hospitals who provided information on 1515 cases. Eighty-two per cent of the patients completed treatment correctly, 14% defaulted, 5% died, 0.5% failed, and 8.7% interrupted treatment due to transfer or other reasons. The variables associated with default were intravenous drug use (IVDU) (OR 6.00, 95%CI 2.59-13.89) and immigration (OR 8.57, 95%CI 3.78-19.45); sex, age, homelessness, incarceration, directly observed treatment (DOT) or hospitalisation were not associated with default. Variables found to be predictive of fatality were alcoholism (OR 6.38, 95%CI 2.09-19.48), human immunodeficiency virus (HIV) infection (OR 7.08, 95%CI 2.08-29.15) and age >64 years (OR 10, 95%CI 2.9-34.07), whereas sex, IVDU, homelessness, DOT and hospitalisation were not. CONCLUSIONS: In industrialised countries, IVDU patients and immigrants should be targeted for DOT, while to reduce fatality rates stricter monitoring is required for patients who are alcoholic, HIV-infected, or aged >64 years.

Characteristics of tuberculosis patients who generate secondary cases.

OBJECTIVE: To determine the characteristics of smear positive tuberculosis (TB) patients who generate secondary TB cases. METHODS: Those smear positive TB patients detected by the Barcelona Tuberculosis Program between 1990-1993, and for whom contact studies had been performed, were studied. We analyzed the predictive role of the variables: age, sex, intravenous drug use (IVDU), the presence of the acquired immune deficiency syndrome (AIDS), human immunodeficiency virus (HIV) infection, radiology pattern, district of residence, history of imprisonment, alcoholism, smoking, history of TB, treatment compliance and the number of secondary cases generated. Statistical analysis was based on the logistic regression model, calculating the odds ratios (OR) with 95% confidence intervals (CI). RESULTS: Of the 1079 patients studied, 78 (7.2%) had generated only one secondary case, and 30 (2.8%) two or more. The variables associated with generating two or more secondary cases were: IVDU (P < 0.001; OR = 4.06; CI: 1.80-9.15), cavitary radiology pattern (P = 0.002; OR = 3.69; CI: 1.62-8.43), and age (P = 0.016; OR = 0.98; CI: 0.96-0.99). When we examined those who had generated one or more secondary cases, the following variables were significant: IVDU (P = 0.043; OR = 1.75; CI: 1.02-3.02), cavitary radiology pattern (P < 0.001; OR = 3.07; CI: 1.98-4.77) and age (P < 0.001; OR = 0.98; CI: 0.97-0.99). CONCLUSION: The study of the contacts of smear positive TB patients allows us to detect an important number of secondary cases. Young adults, those with cavitary radiology pattern, and IVDU are more likely to generate secondary cases.

Proposing indicators for evaluation of tuberculosis control programmes in large cities based on the experience of Barcelona.

OBJECTIVE: To evaluate the effectiveness of the Barcelona Tuberculosis (TB) Control Programme and to propose evaluation indicators. MATERIALS AND METHODS: Using quantitative indicators, the results and impact of the programme over the period 1987 to 1999 were evaluated. Statistical analysis was based on a description of indicators, including tests for trends, and on the evolution of the incidence. RESULTS: The incidence of tuberculosis rose between 1987 and 1991 (P = 0.10), and fell between 1991 and 1999 (P < 0.001). During the study period statistically significant improvements were observed in the percentage of cases notified by the medical profession, adherence to treatment and the percentage of cases on directly observed treatment (DOT), and meningitis among children aged 0 to 4 years fell notably. However, diagnostic delay in smear-positive cases and the percentage of cases whose contacts were examined did not vary significantly. The evaluation indicated an average annual decline in tuberculosis incidence of 6.7%, and rates of adherence to treatment (94.5% among smear-positive cases) achieved their objectives. The average median diagnostic delay (36 days) and the percentage of cases with contacts examined (mean 59.8%) were rather less optimistic. CONCLUSIONS: The results of the evaluation were in general positive. Decline in incidence, meningitis in children, treatment adherence rates, diagnostic delay and percentage of cases with studied contacts were considered the best indicators for evaluation of TB programmes.

Tuberculosis infection and disease among schoolchildren: the influence of the HIV epidemic and of other factors.

BACKGROUND: The HIV/AIDS epidemic has caused an excess of tuberculosis cases in Spain and in other countries, but its impact on tuberculosis infection is less well understood. This study presents a massive screening undertaken to estimate the prevalence of tuberculous infection in a cohort of primary school entrants. The evolution of the risk of infection is studied by comparison with previous data in the same population. METHODS: Tuberculin skin test screening with 2TU of PPD RT 23 of first grade students in the primary schools of Barcelona, in the 1994-95 school year (cohort born in 1988). Information was also sought from families of unscreened children. Contacts of PPD+ children were traced to locate index cases. The results were also linked to the case registry of the tuberculosis control programme. RESULTS: The prevalence of tuberculin reactors free of BCG vaccination among the 11,080 schoolchildren screened belonging to the 1988 cohort was 0.76%. A 3% annual decline in the annual risk of infection is estimated by comparison with previous data. The identification of 24 cases with a previous history of tuberculosis disease and of 13 cases with active disease diagnosed after the screening was possible by the follow up of these tuberculin positive children and of the information provided by families of unscreened pupils. The screening detected 1.5 new cases of tuberculosis per 1000 tuberculin tests performed. Tuberculosis infection could be traced to HIV infected tuberculosis cases for at least 6% of the positive schoolchildren. CONCLUSIONS: The decline of the annual risk of infection continues in Barcelona, although at a slower pace than before the HIV/AIDS epidemic, probably attributable to the influence of injecting drug users with smear positive tuberculosis and HIV/AIDS.

[Evidence-based tuberculosis control: a public health approach]. / El control de la tuberculosis basado en la evidencia: una aproximación de salud pública.

Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. One of the differential traits of the practice of public health when compared to clinical medicine is that it does not concentrate in individual patients, but rather in the health problems of the population in a given time. In public health interventions, besides the importance of efficacy, aspects related to the process of implementation become also crucial. This paper develops some principles for evidence-based public health, which are then applied to a given problem: tuberculosis control in our context. Tuberculosis control poses challenges which go beyond clinical practice, and require a collective organized effort. This is precisely what makes it a public health issue and not only a clinical problem, as it requires not only health care dimensions but also public health dimensions, which require policies that are feasible, have high efficacy, and a moderate cost. To illustrate the problem and the results of public health policies, available data and indicators are used, with special reference to the authors experience in the program for the prevention and control of tuberculosis in Barcelona (Catalonia, Spain).

[Tuberculosis trends in Barcelona (1987-1995). Impact of the human immunodeficiency virus and control measures]. / Evolución de la tuberculosis en Barcelona (1987-1995). Influencia del virus de la inmunodeficiencia humana y de las medidas de control.

BACKGROUND: To study the epidemiology to tuberculosis (TB) in Barcelona, Spain from 1987 to 1995, analyzing the influence of HIV infection and the impact of control measures. PATIENTS, MATERIAL AND METHODS: All cases detected by the Barcelona Tuberculosis Prevention and Control Program were included in the study of the evolution of TB incidence according to different variables. The impact of HIV infection was analyzed through the attributable risk per cent (AR), and control measures through the evolution of the rate of treatment compliance, contact studies, and diagnostic delay. RESULTS: We detected 8,942 patients, 23.2% of whom were found through the active epidemiological surveillance system, representing an average annual incidence of 60.4/100,000. The incidence peaked in 1991 (68.7/100,000) and slowly declined to 55.7/100,000 in 1995. Men showed higher incidence (RR: 2.74; CI 95%: 2.62-2.87), particularly among the young (25-34 years olds), 53.3% of whom were HIV (+). The AR for HIV was 92.7%. In this period there was an increase in TB HIV (+), IVDU, and prisoners. Treatment compliance (80.8% in 1987 to 93.8% in 1995) and contact studies (3.2 studies/case in 1995) evolved favorably, unlike but diagnostic delay (35 days in 1995) did not. CONCLUSIONS: The Active Epidemiological Surveillance System has affored us a clear view of the actual situation regarding TB in Barcelona, Spain. Despite the HIV epidemics and the high number of IVDU, the evolution of TB has shown a steady decline due to improvement in control measures.

[Evaluation of the tuberculosis control programs of the autonomous regions of Spain]. / Evaluación de los programas de control de tuberculosis de las Comunidades Autónomas de España.

BACKGROUND: After the resurgence of tuberculosis in the eighties, several institutions pushed to rapidly create tuberculosis programs and to improve the effectiveness of those in existence. The objective of this paper is to evaluate the programs of the Autonomous Communities of Spain. MATERIAL AND METHODS: A questionnaire was sent to 17 Autonomous Communities and two cities Ceuta and Melilla. A table with minimum objectives was made in order to evaluate the impact of each program. The study period was 1996. RESULTS: The percentage of answers was 100%. Fourteen Autonomous Communities (82%) confirmed they have a tuberculosis program, but with important limitations. There are 3.8 public health workers per 1,000 cases of tuberculosis. Eleven Autonomous Communities had active surveillance, but only 4 know adherence rates to tuberculosis treatments, 3 had supervised treatments, and 3 know diagnostic delays. Ten know results about the percentage of cases with revised contacts. 70% of 19 revised programs did not fulfill the recommended basic objectives. CONCLUSIONS: Tuberculosis control in Spain is not adequate for a developed country. An improvement of the programs in needed, with increase of resources and with reference support centers which would carry out annual evaluations.

[Cholera in the world. The cholera epidemic of 1991 in Peru]. / El cólera en el mundo. La epidemia de cólera de 1991 en el Perú.

The objective of this article was to review the epidemic of cholera disease that affected Peru in 1991, its epidemiologic impact and the natural regions most affected. Also it is reviewed the state of this epidemic two years after. A description of the incidence of natural regions, the main mechanisms of transmission and the control strategy that public health authorities hold on. This review concludes that professionals and public health authorities should be prepared to control this disease, that can suddenly erupt in any country or region, due to the easy way of transmission of Vibrio cholerae.

[Influence of social inequality, social unrest and extreme poverty on tuberculosis morbidity in the City of Barcelona]. / Influencia de las desigualdades sociales, la conflictividad social y la pobreza extrema sobre la morbilidad por tuberculosis en la ciudad de Barcelona.

BACKGROUND: The main purpose of this study was to analyse inequalities between tuberculosis/intravenous drug user and tuberculosis/not intravenous drug user among the different neighbourhoods of Barcelona and the relationship to socioeconomic indicators and social/material deprivation indicators throughout the 1990-1995 period. METHODS: An ecological study which included all cases of tuberculosis among residents of Barcelona, the analysis unit being the neighbourhood. Intravenous drug users within the 15-49 age range and non-intravenous drug users over age 14 were included. The mean annual incidence rate standardized by age was used. The social indicators considered were the inner city areas, unemployment, less than primary education, overcrowding, social unrest and extreme poverty. In the bivariate analysis, the relationship between tuberculosis incidence and the social indicators was studied by means of the Spearman correlation coefficient, and the multivariate analysis by means of the Poisson regression. RESULTS: The incidence rates were higher in the inner city neighbourhoods, followed by the newer outlying working class neighbourhoods in both groups studied, and in other older outlying districts for the non-users of intravenous drugs. Among the intravenous drug user group, the variables related to a greater risk of tuberculosis were: man (RR = 7.42, confidence interval at 95% ICI95%-: 6.16-8.93), age (RR = 61.51, CI95%: 34.64-109.20), unemployment (RR = 1.68, CI95%: 1.51-1.88), social unrest (RR = 1.29, CI 95%: 1.04-1.58), overcrowding (RR = 1.36, CI 95%: 1.19-1.55) and inner city areas (RR = 1.92, CI 95% 1.48-2.50). Among the male non-users of intravenous drugs, no interaction between unemployment and age was found. Neighbourhoods with extreme poverty and inner city neighbourhoods showed a higher risk of tuberculosis (RR = 1.11, CI 95% 1.08-1.135 and RR = 1.80, CI95%: 1.51-2.14). Among the female non-users of intravenous drugs, a relationship was found in those of lesser age (RR = 1.29, CI 95%: 1.05-1.57), unemployment (RR = 1.18, CI 95%: 1.09-1.26), extreme poverty (RR = 1.95, CI 95%: 1.56-2.45) and inner city areas (RR = 1.72, CI 95%: 1.35-2.19). CONCLUSION: Inequalities in tuberculosis are related to different social indicators such as unemployment and inner city areas. A difference exists between the two groups studied. Tuberculosis is related with social unrest and overcrowding among intravenous drug users and with extreme poverty among non-users of intravenous drugs.

Screening for tuberculosis upon admission to shelters and free-meal services.

BACKGROUND: The homeless are at very high risk of suffering tuberculosis (TB). The aims of this study were to determine the prevalence and risk factors for tuberculosis infection and disease among the homeless in Barcelona and to evaluate the roles of case finding and contact investigation. METHODS: Observational prevalence study carried out between 1997 and 1998. PARTICIPANTS: 447 homeless patients (394 men and 53 women) were evaluated before admission to shelters and free-meal services. At the same time, 48 co-residents with smear-positive TB patients in 2 long-term shelters were evaluated too. A chest X-ray and Tuberculin Skin Test were performed on all subjects. Sputum smears were processed by the Ziehl-Neelsen and Löwenstein-Jensen procedures in patients with radiographic findings consistent with pulmonary TB. RESULTS: Of the 447 homeless examined, 335 (75%) were infected with Mycobacterium tuberculosis. Active pulmonary TB was diagnosed in five persons (1.11%), and 62 (13.8%) had radiographic evidence of inactive pulmonary TB. Tuberculosis infection was associated with age and smoking, but not with sex or alcohol abuse. No significant differences in infection rates were found between the main group and 48 homeless co-residents of smear-positive subjects. Only 16.9% of the homeless with active TB in Barcelona in the same period were diagnosed through active case-finding, the remainder being mainly detected in hospitals (69.8%) and other several centres (13.3%). CONCLUSIONS: Homeless individuals have a very high risk of TB infection and disease and contact investigation requires specific methods for them. Programmes of screening and supervised treatment should be ensured in this group.