Poly-drug use among female and male commercial sex workers visiting a drop in centre in Mombasa County, Kenya

{"Background": "The relationship between commercial sex work and drug use is complex and bidirectional. In Kenya, Mombasa County has one of the highest populations of drug users and commercial sex workers. While drug use among sex workers has been documented, most studies rely on self-reported history, which is prone to social desirability and memory recall biases. This study sought to determine actual drug use patterns using both self-reported history and saliva-based drug testing among commercial sex workers in Mombasa.", "Methods": "A cross-sectional study was conducted between February and April 2018 at Mvita Drop-in Service Centre in Mombasa County, Kenya. A total of 224 commercial sex workers aged \u226518 years who had been accessing services at the centre for at least one month were recruited using convenience and snowball sampling. Social-demographic characteristics and self-reported drug use history were documented using a participant-assisted questionnaire. Actual drug use was determined qualitatively using a 6-panel plus alcohol Saliva Test kit, which detects cocaine, opiates, tetrahydrocannabinol (THC), amphetamine, benzodiazepines, cotinine, and alcohol. Statistical analysis included chi-square tests, Fisher's exact tests, Cohen's Kappa coefficient for agreement between self-reported and confirmed drug use, and Venn diagrams for poly-drug combinations. Analysis was performed using Stata version 15.1 and R statistical software version 3.6.2.", "Key Results": "Of 224 participants, 220 (98%) reported current use of at least one drug, and among the 196 who consented to saliva testing, 194 (99%) tested positive for at least one drug. The most commonly self-reported drugs were alcohol (71%), cigarette (63%), shisha (38%), khat (31%), heroin (28%), and marijuana (21%). Saliva test results showed alcohol (68%), cotinine (63%), opioids (28%), THC (17%), amphetamine (16%), cocaine (8.2%), and benzodiazepines (7.7%). Poly-drug use was nearly universal: 98% of those tested positive for more than one drug, with only 2.02% being mono-drug users. The most common combination detected was alcohol, cotinine, THC, and opioids. Alcohol use increased significantly with age (94% in >35 years vs 68% in 18\u201335 years, P=0.03). Cigarette use was higher among younger participants (65% in 18\u201335 years vs 24% in >35 years, P=0.001), and cotinine positivity was also higher in the younger group (66% vs 25%, P=0.002). Heroin use was higher among males (49% vs 22%, P<0.001) and among those in formal employment (57%, P=0.007). Agreement between self-reported and confirmed drug use ranged from moderate to almost perfect: heroin/opioids (Kappa=0.91, 95%CI 0.85\u20130.98), cigarette/cotinine (Kappa=0.79, 95%CI 0.70\u20130.88), cocaine (Kappa=0.64, 95%CI 0.43\u20130.86), khat/amphetamine (Kappa=0.54, 95%CI 0.41\u20130.68), alcohol (Kappa=0.53, 95%CI 0.40\u20130.66), and marijuana/THC (Kappa=0.48, 95%CI 0.32\u20130.64). Among those reporting drug use, 84% were initiated by friends, 94% used drugs daily, 88% cited sex work-related pressure as the reason, and 60% reported they cannot transact sex work without drugs. The majority (79%) had used drugs for more than three years.", "Clinical Implications": "This study demonstrates that drug use, particularly poly-drug use, is nearly universal among commercial sex workers in Mombasa, with alcohol and tobacco being the most prevalent substances. The high concordance between self-reported and saliva-confirmed drug use for most substances (especially heroin/opioids and cigarette/cotinine) suggests that self-report can be reasonably reliable for some drugs in this population, though underreporting remains a concern. The finding that 60% of respondents cannot engage in sex work without drugs, and that 88% attribute use to work-related pressure, indicates that drug use is deeply embedded in the sex work environment. Targeted interventions should include harm reduction services, addiction counseling, economic empowerment through vocational training, and structural interventions addressing the social and economic drivers that link sex work and drug use. The high prevalence of alcohol and tobacco use also warrants integration of brief interventions and cessation support into existing sexual reproductive health services for this population."}