DSpace Collection: Theses in Epidemiology and Medical Statistics

MODELS FOR PREDICTING TIME TO SPUTUM CONVERSION AMONG MULTI-DRUG RESISTANT TUBERCULOSIS PATIENTS IN LAGOS, NIGERIA

2019-09-27T10:45:16Z

Title: MODELS FOR PREDICTING TIME TO SPUTUM CONVERSION AMONG MULTI-DRUG RESISTANT TUBERCULOSIS PATIENTS IN LAGOS, NIGERIA Authors: AKINSOLA, O.J. Abstract: Multi-drug resistant tuberculosis (MDR-TB) develops due to problems such as irregular drug supply, poor drug quality, inappropriate prescription and poor adherence to treatment. These factors allow the development and subsequent transmission of resistant strains of the pathogen. With the advancements in statistics, mixture cure models provide the insight to the covariates that are related with the treatment outcomes. However, potential modifiable factors such as demographic and clinical characteristics are not clearly known in poor resource settings such as Nigeria. Therefore, this study was designed to determine the factors that can predict time to sputum conversion among MDR-TB patients using cure model. A retrospective clinic-based cohort study was conducted on 413 patients who were diagnosed of multi-drug resistant tuberculosis and met inclusion criteria from April 2012 to October 2016 at the Infectious Disease Hospital, Lagos. The main outcome measure (sputum conversion time) was the time from the date of commencement or MDR-TB treatment to the date of specimen collection for the first of two-consecutive negative smear and culture taken 30 days apart. The predictor variables of interest include: demographic (age, gender and marital status) and clinical characteristics (registration group, number of drugs resistant to during treatment initiation, HIV status, diabetes status and adherence with medication). Mixture Cox cure models were fitted to the main outcome variable using Log-normal, Log-logistic and Weibull distributions as alternatives to the violation of Proportional Hazards (PH) assumption. Akaike Information Criterion (AIC) was used for models comparison based on different distributions, while the effect of predictors of time to sputum conversion was reported as Hazard Ratio (HR) at a0.05. Age was 36.8±12.7 years, 60.8% were male and 67.6% were married. Majority of the patients (58.4%) converted to .sputum negative. Patients who were resistant to two drugs at treatment initiation had 39.0% rate of conversion than those resistant to at least three drugs [HR: 1.39 (CI:0.98, 1.98)]. The likelihood of sputum conversion time was shorter among non-diabetic patients compared to diabetics [HR: 0.55: (CI: 0.24, 0.85)]. The overall median time for sputum conversion was 5.5 (IQR: 1.5-11.5) months. In the cure model, resistance to more drugs at the time of initiation was significantly related with a longer sputum conversion time for Log normal Cox mixture [HR: 2.06 (CI: 1.36-3.47)]; Log-logistic Cox mixture cure [HR: 2.56 (CI: 1.85- 4.09)] and Weibull Cox mixture [HR: 2.81 (CI: 1.94-4.19)]. Diabetic patients had a significantly higher sputum conversion rate compared to non-diabetics; Log-normal Cox mixture [HR: 2.03 (CI: 1.17-3.58)); Log-logistic Cox mixture cure I I-IR: 2.11 (CI: 1.25-3.82)) and Weibull Cox mixture [HR: 2.02 (CI: 1.17-3.34)). However, Log-normal PH model gave the best fit and provided the fitness statistics [(-2LogL: 519.84); (AIC: 1053.68)). The best fitting Log-normal PH model was Y=1.00X1+2.06X2+0.98X3+2.03X1 I-E where Y is time to sputum conversion and X5 are age, number of drugs, adherence and diabetes status. The models confirmed the presence of some factors related with sputum conversion time in Nigeria. The quantum of drugs resistant at treatment initiation and diabetes status would aid the clinicians in predicting the rate of sputum conversion of patients. Description: A Thesis submitted to the Department of Epidemiology and Medical Statistics, Faculty of Public Health, College of Medicine, University of Ibadan, in partial fulfillment for the requirement of the award of Doctor of Philosophy in Biostatistics of the University of Ibadan, Nigeria.

ROBUSTNESS OF POISSON-MIXTURE MODELS IN IDENTIFYING RISK FACTORS OF UNDER-FIVE MORTALITY IN NIGERIA

2019-08-29T10:13:41Z

Title: ROBUSTNESS OF POISSON-MIXTURE MODELS IN IDENTIFYING RISK FACTORS OF UNDER-FIVE MORTALITY IN NIGERIA Authors: ORITOGUN, K.S. Abstract: Under-five Mortality (U5M) is a public health concern. There is a dearth of credible statistics on its risk factors attributable to the weak vital registration system in developing countries including Nigeria. Estimates of U5M have taken advantage of indirect methods but U5M risk factors have been identified using fixed statistical models with little considerations for the potentials of mixture models. Mixture models such as Poisson-Mixture models exhibit flexibility tendency which is an attribute of robustness lacking in fixed models. Therefore, this study was carried out to examine the robustness of Poisson-Mixture models in identifying reliable determinants of U5M. The data on 18,855 women used in this study was from the 2008 Nigeria Demographic and Health Survey (NDHS). A stratified, two-stage cluster sampling design was adopted for the study. Birth history of women aged 15-49 years, survival of under-five children and their socio-demographic characteristics were collected by personal interviews using a structured questionnaire. Six different Poisson-Mixture models namely: Poisson (PO), Zero-Inflated Poisson (ZIP), Poisson Hurdle (PH), Negative Binomial (NBI), Zero-Inflated Negative Binomial (ZINBI) and Negative Binomial Hurdle (NBJH) were fitted separately to the data. The Akaike Information Criteria (AIC) and diagnostic check for normality were used to select robust models within Mosley and Chen analytical framework. Infant and child mortality were also considered. All tests were conducted at p=0.05. The NDHS data on USM and the associated factors had different distributions at National and Zonal levels. The models and AIC values for U5M were: 38763.47 (PO), 38654.55 (ZIP), 44270. 77 (PH), 38526.26 (NBI), 38513. 71 (ZINBI) and 44269.30 (NBIH). The PO, ZIP, PH and NBIH met normality test criteria and the ZIP model was of best fit. Also, the Infant mortality models and their AIC values were: 15167.95 (PO), 15169.95 (ZIP), 17568.57 (PH), 15105.42 (NBI), 15107.42 (ZINBI) and 17566.18 (NBIH). Among the models, PO, PH, and NBIH which met the normality test criteria, only the PO model with the smallest AIC had the best fit. Similarly, the models and AIC values for Child Mortality were 22854.13 (PO), 22765.75 (ZIP), 26528.66 (PH), 22708.97 (NBI). 22692.48 (ZINBI) and 26530.64 (NBIH). The ZINBI model with the smallest AIC gave the best fit. These models identified breastfeeding, mother's weight, paternal education, toilet type, maternal education, place of delivery, birth-order and antenatal-visits as significant determinants of infant, Child and U5M at the national level, while breastfeeding, mothers weight, paternal education and toilet type had significant effects on U5M in North-East and North-West Zones. Maternal education had significant association with U5M in South-East and South-South Zones. Breastfeeding, toilet type, maternal education and woman's age were significantly associated with U5M in the North-Central zone. Also, breastfeeding, maternal education, birth-order and antenatal-visits were significantly associated with U5M in the South-West zone. For all models, maternal education was significantly associated with U5M. The Zero-Inflated Poisson model provided the best robust estimates of Under-five Mortality in Nigeria, while maternal education was identified as the most important determinant. The Poisson-mixture models are recommended for modelling Under-five Mortality in Nigeria. Description: A Thesis in the Department of Epidemiology and Medical Statistics, submitted to the Faculty of Public Health, College of Medicine, University of Ibadan in partial fulfillment of requirements for the Degree of Doctor of Philosophy of the University of Ibadan, Nigeria.

EVALUATION OF A TRAINING INTERVENTION ON THE PROVISION OF ORAL HEALTH SERVICES AMONG PRIMARY HEALTH CARE WORKERS IN KWARA STATE, NIGERIA

2019-08-07T18:46:30Z

Title: EVALUATION OF A TRAINING INTERVENTION ON THE PROVISION OF ORAL HEALTH SERVICES AMONG PRIMARY HEALTH CARE WORKERS IN KWARA STATE, NIGERIA Authors: TOBIN, A.O. Abstract: Oral diseases are prevalent in Nigeria. There is shortage of dental staff especially at the Primary Health Care (PHC) level. Training of non-dental staff and engaging them in Oral Health services (OHS) will improve OHS coverage. Oral Health (OH) knowledge and the effect of a training intervention among PHC workers, patient's perception of health workers (HWs) practice as well as prevalent Oral Conditions (OC) among community members in Kwara state, Nigeria were assessed. Using a quasi-experimental study design, a four stage sampling technique was used to select 12 health facilities (HFs) from 12 wards in four Local Government Areas (LGAs) which were randomised into intervention (2) and control (2) groups from a total of 16 LGAs. A total of 115 (58 control, 57 intervention) consenting HWs from the selected HFs were interviewed. At baseline information on socio-demographics and knowledge of OH was collected, knowledge of OH was computed on a 22-point scale; scores > 16 were classified as good and ≤16 poor. An interviewer-administered questionnaire to assess patient's perception of HWs' OH practice was administered to 1035 (525 control, 510 intervention) consecutive patients attending the HFs. Patient's perception of HWs' practice was computed on a 13-point scale; scores >5 were classified as good and ≤ 5 poor. Prevalence of OC among 150 randomly selected community members was determined. One day training with two follow-up sessions over two months was conducted for HWs in the intervention group. Training elements included oral anatomy, diagnosis, and prevention of common oral diseases. Evaluation of HWs knowledge and patients assessment of HWs practice was conducted six months later. Data were analysed using descriptive statistics, Pearson and McNemars chi-square tests and logistic regression, p=0.05. Age of HWs was 40.1±8 years. Females were 89.6%. Community Health Extension Workers were 47.0%, nurses 34.8% and 'others' such as technicians 18.3%.The proportion of HWs (control) with good baseline and post-intervention knowledge of OH was 44.8% and 29.3%, respectively. The knowledge score was 15.4±2.9 at pre-intervention and 14.6±3.0 at post-intervention. For intervention group knowledge significantly improved from 43.9% to 64.9%, while the knowledge score was 15.6±3.6 and 16.8±2.3 pre and post-intervention, respectively. The odds of better knowledge of OH was 3.0 among nurses compared to 'others' (95.0% CI: 0.97-8.33). Pre and post-intervention perception of HWs practice of providing OH services as good significantly increased from 9.8% to 52.0% (intervention) and 4.2% to 11.0% (control). Perception score for the intervention group pre-intervention was 0.0 (range = 0-9) and 6.4±2.1 post-intervention. The perception score for the control group was not significant pre and post-intervention. Most prevalent OC were plaque and calculus (66.0%). Oral health training intervention improved the provision of oral health services by nondental staff. Training of health workers should be encouraged to bridge knowledge gap on oral health, towards reducing the prevalence of oral conditions. Description: A Thesis submitted to the Department of Epidemiology and Medical Statistics, Faculty of Public Health, College of Medicine, University of Ibadan, in partial fulfillment for the requirement of the award of the Degree of Doctor of Philosophy (Ph.D. Epidemiology) of the University of Ibadan, Nigeria.

DEMOGRAPHIC AND BEHAVIOURAL FACTORS INFLUENCING THE UPTAKE OF VOLUNTARY COUNSELLING AND TESTING AMONG FEMALE SEX WORKERS: A SECONDARY DATA ANALYSIS OF 2007 IBBSS

2019-07-04T11:46:59Z

Title: DEMOGRAPHIC AND BEHAVIOURAL FACTORS INFLUENCING THE UPTAKE OF VOLUNTARY COUNSELLING AND TESTING AMONG FEMALE SEX WORKERS: A SECONDARY DATA ANALYSIS OF 2007 IBBSS Authors: MUMUNI, T.O. Abstract: Despite vigorous promotion, the uptake of Voluntary Counselling and Testing (VCT) has been low overall in sub-Saharan Africa, Nigeria inclusive. The large majority of HIV-1 infected people in sub-Saharan Africa are not aware of their HIV status. Population subgroups such as female sex workers (FSW) are at increased risk of contracting HIV due to their high risk sexual and other behaviours. This group remains under diagnosed despite their level of HIV risk and also they do not patronize VCT services. Hence the need to identify those demographic and behavioural factors which may serve as determinants of VCT uptake among FSWs. The study was a secondary data analysis of HIV testing among the FSW arm of the IBBSS 2007, a cross sectional survey of high risk groups for HIV in six states in Nigeria. The study included 2889 female sex workers. Data was analysed using SPSS version 15.0. Univariate analysis was employed to calculate frequencies and distributions of each variable.Chi-square test was used for bivariate analyses to determine the significance of the association between categorical variables and sexual and behavioural risk factors and VCT uptake. Logistic regression analysis was performed to identify the factors associated with the outcome variable. A p-value <0.05 was considered to indicate statistical significance. The mean age of the sex workers was 26.1 years (SD 5.8 years) and ranged between 15-49 years. The mean ages were similar between brothel based (26.6 years SD 6.1 years)and non-brothel based sex workers (25.5 years SD 5.4 years). Prevalence of VCT among female sex workers was 43.0%. After adjusting for other variables, those with another income source were about twice likely to have received VCT compared to those without another income source (OR=1.526, 95%CI=1.180-1.975). Brothel based sex workers are about three times more likely than non-brothel based sex workers to receive VCT (OR=2.314,95% CI=1.780-3.007). Female sex workers who had knowledge of a facility to receive VCT were twice likely to have had VCT compared to those who did not (OR=1.978, 95%CI=1.580-2.476). Also, female sex workers who had knowledge of the price of VCT were about nine times more likely than those without the knowledge of the price of VCT to have had a VCT (OR=S.230, 95%CI=5.195-13.036). The study shows that the factors influencing the uptake of VCT vary between female sex workers. HlV testing services should be made readily available to FSW with more attention paid to non-brothel based FSWs Who are less likely to have had a HIV test. Innovative methods of reaching this special group and improving VCT need to be developed. Description: A Thesis submitted to the Department of Epidemiology, Medical Statistics and Environmental Health (EMSEH), College of Medicine, University of Ibadan, in partial fulfillment of the requirement of the award of Masters of Epidemiology of the University of Ibadan, Nigeria.