Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Gachau S[original query] |
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Shifting reasons for older men remaining uncircumcised: Findings from a pre- and post-demand creation intervention among men aged 25-39 years in western Kenya
Agot K , Onyango J , Otieno G , Musingila P , Gachau S , Ochillo M , Grund J , Joseph R , Mboya E , Ohaga S , Omondi D , Odoyo-June E . PLOS Glob Public Health 2024 4 (5) e0003188 Voluntary medical male circumcision (VMMC) reduces men's risk of acquiring Human immunodeficiency virus (HIV) through vaginal sex. However, VMMC uptake remains lowest among Kenyan men ages 25-39 years among whom the impact on reducing population-level HIV incidence was estimated to be greatest at the start of the study in 2014. We conducted a pre- and post-intervention survey as part of a cluster randomized controlled trial to determine the effect of two interventions (interpersonal communication (IPC) and dedicated service outlets (DSO), delivered individually or together) on improving VMMC uptake among men ages 25-39 years in western Kenya between 2014 and 2016. The study had three intervention arms and a control arm. In arm one, an IPC toolkit was used to address barriers to VMMC. In arm two, men were referred to DSO that were modified to address their preferences. Arm three combined the IPC and DSO. The control arm had standard of care. At baseline, uncircumcised men ranked the top three reasons for remaining uncircumcised. An IPC demand creation toolkit was used to address the identified barriers and men were referred for VMMC at study-designated facilities. At follow-up, those who remained uncircumcised were again asked to rank the top three reasons for not getting circumcised. There was inconsistency in ranking of reported barriers at pre- and post- intervention: 'time/venue not convenient' was ranked third at baseline and seventh at follow-up; 'too busy to go for circumcision' was tenth at baseline but second at follow-up, and concern about 'what I/family will eat' was ranked first at both baseline and follow-up, but the proportion reduced from 62% to 28%. Men ages 25-39 years cited a variety of logistical and psychosocial barriers to receiving VMMC. After exposure to IPC, most of these barriers shifted while some remained the same. Additional innovative interventions to address on-going and shifting barriers may help improve VMMC uptake among older men. |
Pairwise fitting of piecewise mixed models for the joint modeling of multivariate longitudinal outcomes, in a randomized crossover trial
Mwangi M , Molenberghs G , Njagi EN , Mwalili S , Braekers R , Florez AJ , Gachau S , Bukania ZN , Verbeke G . Biom J 2024 66 (2) e2200333 Many statistical models have been proposed in the literature for the analysis of longitudinal data. One may propose to model two or more correlated longitudinal processes simultaneously, with a goal of understanding their association over time. Joint modeling is then required to carefully study the association structure among the outcomes as well as drawing joint inferences about the different outcomes. In this study, we sought to model the associations among six nutrition outcomes while circumventing the computational challenge posed by their clustered and high-dimensional nature. We analyzed data from a 2 × 2 randomized crossover trial conducted in Kenya, to compare the effect of high-dose and low-dose iodine in household salt on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in women of reproductive age and their household matching pair of school-aged children. Two additional outcomes, namely, urinary iodine concentration (UIC) in women and children were measured repeatedly to monitor the amount of iodine excreted through urine. We extended the model proposed by Mwangi et al. (2021, Communications in Statistics: Case Studies, Data Analysis and Applications, 7(3), 413-431) allowing flexible piecewise joint models for six outcomes to depend on separate random effects, which are themselves correlated. This entailed fitting 15 bivariate general linear mixed models and deriving inference for the joint model using pseudo-likelihood theory. We analyzed the outcomes separately and jointly using piecewise linear mixed-effects (PLME) model and further validated the results using current state-of-the-art Jones and Kenward methodology (JKME model) used for analyzing randomized crossover trials. The results indicate that high-dose iodine in salt significantly reduced blood pressure (BP) compared to low-dose iodine in salt. Estimates for the random effects and residual error components showed that SBP and DBP had strong positive correlation, with effect of the random slope indicating that significantly related outcomes are strongly associated in their evolution. There was a moderately strong inverse relationship between evolutions of UIC and BP both in women and children. These findings confirmed the original hypothesis that high-dose iodine salt has significant lowering effect on BP. We further sought to evaluate the performance of our proposed PLME model against the widely used JKME model, within the multivariate joint modeling framework through a simulation study mimicking a 2 × 2 crossover design. From our findings, the multivariate joint PLME model performed exceptionally well both in estimation of random-effects matrix (G) and Hessian matrix (H), allowing satisfactory model convergence during estimation. It allowed a more complex fit to the data with both random intercepts and slopes effects compared to the multivariate joint JKME model that allowed for random intercepts only. When a hierarchical viewpoint is adopted, in the sense that outcomes are specified conditionally upon random effects, the variance-covariance matrix of the random effects must be positive definite. In some cases, additional random effects could explain much variability in the data, thus improving precision in estimation of the estimands (effect size) parameters. The key highlight in this evaluation shows that multivariate joint JKME model is a powerful tool especially while fitting mixed models with random intercepts only, in crossover design settings. Addition of random slopes may lead to model complexities in most cases, resulting in unsatisfactory model convergence during estimation. To circumvent convergence pitfalls, extention of JKME model to PLME model allows a more flexible fit to the data (generated from crossover design settings), especially in the multivariate joint modeling framework. |
Uptake and continuation of HIV pre-exposure prophylaxis among women of reproductive age in two health facilities in Kisumu County, Kenya
Ogolla M , Nyabiage OL , Musingila P , Gachau S , Odero TMA , Odoyo-June E , Ochanda B , Appolonia A , Katiku E , Joseph R , Ogolla C , Otieno L , Odhiambo F , Truong HM . J Int AIDS Soc 2023 26 (3) e26069 INTRODUCTION: In 2020, Kenya had 19,000 new HIV infections among women aged 15+ years. Studies have shown sub-optimal oral pre-exposure prophylaxis (PrEP) use among sub-populations of women. We assessed the uptake and continuation of oral PrEP among women 15-49 years in two health facilities in Kisumu County, Kenya. METHODS: A retrospective cohort of 262 women aged 15-49 years, initiated into oral PrEP between 12 November 2019 and 31 March 2021, was identified from two health facilities in the urban setting of Kisumu County, Kenya. Data on baseline characteristics and oral PrEP continuation at months 1, 3 and 6 were abstracted from patient records and summarized using descriptive statistics. Missing data in the predictor variables were imputed within the joint modelling multiple imputation framework. Using logistic regression, we evaluated factors associated with the discontinuation of oral PrEP at month 1. RESULTS: Of the 66,054 women screened, 320 (0.5%) were eligible and 262 (82%) were initiated on oral PrEP. Uptake was higher among women 25-29 years as compared to those 15-24 years (77% vs. 33%). Oral PrEP continuation declined significantly with increasing duration of follow-up; 37% at month 1, 21% at month 3 and 12% at month 6 (p<0.05). In the adjusted analysis, women 15-24 years had lower adjusted odds of continuing at month 1 than women ≥25 years (adjusted odds ratio [aOR]: 0.41, 95% CI: 0.21-0.82). There was no association between being sero-discordant and continuation of oral PrEP at month 1 (aOR; 1.21, 95% CI 0.59-2.50). Women from the sub-county hospital were more likely to continue at month 1 of follow-up compared to women enrolled in the county referral hospital (aOR 5.11; 95% CI 2.24-11.70). CONCLUSIONS: The low eligibility for oral PrEP observed among women 15-49 years in an urban setting with high HIV prevalence calls for a review of the screening process to validate the sensitivity of the screening tool and its proper application. The low uptake and continuation among adolescent girls and young women underscores the need to identify and address specific patient- and facility-level barriers affecting different sub-populations at risk for HIV acquisition. |
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