Dropouts in a long-term follow-up study involving voluntary counseling and HIV testing: experience from a cohort of police officers in Dar Es Salaam, Tanzania

BACKGROUND

Results of most population-based studies primarily are derived from people who responded positively and thereby continued to participate in such studies. It is, however, equally important to know the characteristics of study subjects who drop out to learn the reasons that kept them from continuing to participate in the study, especially because they had initially agreed to participate in such a study. In studies with long-term follow-up, reasons for nonresponse may provide invaluable information that may be gathered through continued contact with study subjects who have withdrawn from the study.

OBJECTIVES

To determine characteristics of study participants who withdrew from an ongoing study of police officers, which involved counseling and HIV testing, and to determine reasons for their discontinued participation.

METHODS

Demographic characteristics of a cohort of police officers who had been participating in a study to determine their suitability for HIV vaccine trials were analyzed. Characteristics of those who did not return for the second survey of appointments for HIV testing were compared with those who continued their participation. A randomly selected sample of 132 police officers who did not participate in the second survey of HIV testing were asked why they did not return. Answers were obtained from 84 people who had discontinued their participation.

RESULTS

Of eligible police officers, 2087 (72.1%) responded to the call for follow-up appointments, whereas 807 (27.9%) did not return. Those who did not return to participate in the second survey had significantly higher rates of HIV seropositivity (17.2%) than those who did return (13.5%) (p <.05). The rate of return in unmarried participants was worse (p <.05) than the rate among married participants. Rates of sexual contacts with partners other than their spouses and levels of alcohol consumption did not differ between the two groups. Reasons for dropping out of the study included fear of knowing results of HIV testing in 54.6%, lack of time to continue in 34.5%, and fears about job security in 3.6%.

CONCLUSION

Fears of finding out that one might be seropositive need to be answered at recruitment, and practical arrangements must be made to facilitate further follow-up. A bias for lower incidence might be introduced in vaccine trials if participants thought to be at highest risk for HIV infection discontinue participation.

Isoniazid prophylaxis for tuberculosis prevention among HIV infected police officers in Dar es Salaam

OBJECTIVE

To determine the acceptability, compliance and side effects of isoniazid (INH) prophylaxis against tuberculosis among HIV infected police officers (PO) in Dar es Salaam.

DESIGN

A nested study from a prospective follow up of a cohort of police officers.

SETTING

Dar es Salaam, Tanzania.

SUBJECTS

One hundred and forty three HIV-1 infected police officers.

MAIN OUTCOME MEASURES

Acceptance and compliance to INH prophylaxis.

RESULTS

Of the 400 HIV-1 infected officers, 143 (35.7%) came forward for post-test counselling and HIV test results. Sixty per cent (87/143) of them accepted to be on INH prophylaxis. However only 42.5% (37/87) came forward for evaluation regarding their suitability for INH prophylaxis. During the evaluation, eight (21.6%) of 37 otherwise asymptomatic PO were found to have active pulmonary tuberculosis (TB). Eventually only 29 PO were actually started on INH, and only 16 (55.2%) of them completed the six months course. No serious side effects were observed. One PO developed TB two months after loss to follow up before completing the six months.

CONCLUSIONS

There was low acceptability of and poor compliance with INH prophylaxis among the HIV-1 infected PO despite being educated on the benefits of prophylaxis. The prevalence of PTB among asymptomatic HIV-1 infected PO was high, and therefore persons with HIV infection should be examined for TB even in the absence of symptoms.