What is the empirical basis for converting banded ordinal data on numbers of sex partners among MSM into a continuous scale level variable? A secondary analysis of 13 surveys across 17 countries

Abstract

Background To provide empirically based guidance for substituting partner number categories in large MSM surveys with mean numbers of sexual and condomless anal intercourse (CAI) partners in a secondary analysis of survey data. Methods We collated data on numbers of sexual and CAI partners reported in a continuous scale (write-in number) in thirteen MSM surveys on sexual health and behaviour across 17 countries. Pooled descriptive statistics for the number of sexual and CAI partners during the last twelve (N = 55,180) and 6 months (N = 31,759) were calculated for two sets of categories commonly used in reporting numbers of sexual partners in sexual behaviour surveys. Results The pooled mean number of partners in the previous 12 months for the total sample was 15.8 partners (SD = 36.6), while the median number of partners was 5 (IQR = 2–15). Means for number of partners in the previous 12 months for the first set of categories were: 16.4 for 11–20 partners (SD = 3.3); 27.8 for 21–30 (SD = 2.8); 38.6 for 31–40 (SD = 2.4); 49.6 for 41–50 (SD = 1.5); and 128.2 for ‘more than 50’ (SD = 98.1). Alternative upper cut-offs: 43.4 for ‘more than 10’ (SD = 57.7); 65.3 for ‘more than 20’ (SD = 70.3). Self-reported partner numbers for both time frames consistently exceeded 200 or 300. While there was substantial variation of overall means across surveys, the means for all chosen categories were very similar. Partner numbers above nine mainly clustered at multiples of tens, regardless of the selected time frame. The overall means for CAI partners were lower than those for sexual partners; however, such difference was completely absent from all categories beyond ten sexual and CAI partners. Conclusions Clustering of reported partner numbers confirm common MSM sexual behaviour surveys’ questionnaire piloting feedback indicating that responses to numbers of sexual partners beyond 10 are best guesses rather than precise counts, but large partner numbers above typical upper cut-offs are common.

Estimating Partnership Duration among MSM in Belgium—A Modeling Study

“…The total numbers of steady and casual partners over a period of 12 months are reported in the EMIS 2017 dataset as categorical variables: 0, 1, 2, …, 9 or 10 or more for steady and 0, 1, 2, …, 10, 11–20, 21–30, 31–40, 41–50 or more than 50 for casual partners. Assuming at most 12 steady partners over 12 months, we used the methodology and statistics described by Mendez-Lopez et al [ 71 ] to build an algorithm to assign integer values to the total number of partners that match the mean (standard deviation) and median (interquartile range) for each category level and overall ( Table 1 ). At each iteration of the algorithm, we randomly assigned persons reporting more than 10 steady partners into the categories of 10, 11 or 12.…”

Still trouble with bleeding: Risk factors for HCV transmission in men who have sex with men and behavioural trajectories from 2019 to 2021

“…More than 10 (more than 20) sex partners were reported by 42.1% (23.4%) of cases versus 31.8% (15.9%) of controls [ p = 0.012 ( p = 0.024)]. When converted into a continuous scale variable [24], the mean number of partners was 24 among cases versus 15 among controls ( p < 0.001). Cases more commonly engaged in sexual practices that have been reported as risk factors in the literature – such as insertive anal intercourse (AI), insertive condomless anal intercourse (CAI), insertive fisting, insertive rimming, receptive AI, receptive CAI, receptive fisting, absence of gloves or shared gloves in fisting, shared fisting lubricant, shared anal sex toys, shared anorectal douching devices – and in sex‐associated drug use behaviours , such as chemsex (use of stimulant drugs to intensify or prolong sex), shared nasally administered drugs (NADs), NADs during group sex, ‘slamming’ (use of injection drugs in a sexual context), shared needles, CCAT, sphincter relaxants (such as ‘poppers’) or partners using phosphodiesterase type 5 inhibitors (such as sildenafil).…”

Social and behavioural determinants of syphilis: Modelling based on repeated cross-sectional surveys from 2010 and 2017 among 278,256 men who have sex with men in 31 European countries

“…To capture risky sexual behaviour with respect to syphilis transmission, we assessed the number of male sexual partners by type and sexual act within the previous 12 months, differentiating whether partners were steady or non-steady, and whether the sexual act included condomless anal intercourse (CAI). 27 Additional behavioural risk factors are whether the respondent engaged in transactional sex, including paying for sex and selling sex during the previous 12 months.…”