Research subjects were selected from among 1573 women enrolled into the feasibility study in Mwanza, Tanzania, who worked in food or recreational facilities (cooked food or local beer vending, bars, restaurants, guesthouses and hotels).9
Women in these occupations in Tanzania are at high risk of HIV/STI.10,11,12
The feasibility study included structured FFIs at enrolment (n
1573), ethnographic fieldwork in 68 food or recreational facilities, focus group discussions on sexual behaviour (six with food or recreational facility workers, two with male customers) and nine open‐ended interviews on vaginal hygiene practices. For the coital diary study, these informed the variables chosen, the design of pictures and instruments and the interpretation of results.
After pre‐testing of five diary designs, a design with pictures and tick boxes was selected. The coital diary covered 7
days and could be used to record up to four sex acts per day. It was 16 cm by 13 cm to fit into a pocket or handbag, and contained seven data entry sheets (representing each day of the week), and information sheets with explanations for each picture. The diary text was translated into Kiswahili and back before production. Fig 1 shows a collection entry page.
Figure 1Coital diary collection entry page. Notes: Pictures show, from left to right: 1. Sex act (anal, vaginal). 2. Male condom. 3. Female condom. 4. Contraception. 5. Decrease and increase in lubrication. 6. Vaginal cleaning. 7. Menstruation. (more ...)
Coital diary evaluation study
We assessed the impact on diary responses of three levels of support by researchers. Diary results were compared with data from FFIs covering two different recall periods (previous week or previous four weeks), either of which FFI might be employed at regular intervals during microbicide trials. The acceptability of the study methods was assessed by interview.
In discussions among Microbicides Development Programme coordinators, it was debated whether FFIs on sexual behaviour should aim to record frequencies over the past four weeks or one week. The preference initially was for four weeks, because a longer time period was thought likely to offer a more representative picture of sexual behaviour, and repeatedly interviewing each week would be more costly. In this paper we therefore focus primarily on comparisons between coital diaries and FFIs covering four weeks.
We selected a subsample of 150 women from participants who were due to attend for a three, six, nine or 12‐month follow‐up visit to mobile study clinics during a six‐week interview period (March to April 2004; N
538). The sample size of 150 participants was chosen according to logistical and human resource constraints, given a number of competing demands on the research team in meeting feasibility study objectives. Recruitment data suggested that there were few differences in women's characteristics or STI prevalence between the 10 wards of Mwanza City from which women were recruited to the feasibility study. For each level of researcher support, five wards were randomly chosen and a random sample of 50 women was selected from eligible participants in these wards. To reduce travel between interviews, we ensured a minimum of 10 participants in each ward for the three support levels combined.
Participants were asked to complete diaries for 28
days. Levels of researcher support were defined as follows:
Minimum – Participants received a scheduled weekly visit to their home or workplace to deliver and collect coital diaries. A FFI (exit interview) was conducted a few days after the final visit, including questions on frequency of sexual behaviour over the entire four‐week study period and on diary study acceptability.
Medium was the same as minimum support, plus during the weekly visit an FFI was administered relating to the previous 7
days and, if participants raised concerns about diary completion, these were discussed.
Intensive – An unscheduled weekly visit was added, at home or the workplace. During this, fieldworkers checked that participants were completing the diary daily and asked about and helped them with any concerns related to the diary.
Questions asked in weekly and exit interviews were closed‐ended, with the exception of some questions concerning interviewee experiences of completing diaries. Responses were recorded manually on questionnaires.
All participants signed or thumb‐printed an informed consent form. Ethics clearance was obtained from the National Medical Research Coordinating Committee, Tanzania and the London School of Hygiene and Tropical Medicine, United Kingdom.
Coital diary and FFI data were summarised as the frequency of each behaviour (a count) and the number of women reporting one or more occurrence of each behaviour (a percentage). Paired statistical tests were used to compare responses on coital diaries, four‐week FFIs and weekly FFIs within women, whereas comparisons of researcher support strategies were between women and so were unpaired. Reported frequencies of behaviours were not normally distributed; they were positively skewed, with many women reporting no occurrences of the behaviours in question. Non‐parametric methods were therefore used for statistical analysis.
For comparisons between coital diaries and the four‐week FFI, the Wilcoxon signed rank test was used for behaviour frequencies and the McNemar test was used for the percentage of women reporting one or more occurrence. These tests were repeated to compare coital diaries with weekly FFIs.
For comparing data by level of researcher support, the Kruskal–Wallis analysis of variance was used to compare behaviour frequencies. Chi‐squared tests were used for the percentage of women reporting one or more occurrence and to analyse the acceptability of the study by support level.
Kappa was used to measure agreement between pairs of instruments in reporting at all, and Spearman's rho to assess agreement in frequencies reported.
In the first week, interviewers mistakenly used a version of the weekly questionnaire that did not contain questions on vaginal cleaning or sex by partner type. Full four‐week data are therefore only available on the weekly interview for other variables.