Modelling immune deterioration, immune recovery and state-specific duration of HIV-infected women with viral load adjustment: using parametric multistate model

Prevalence and associated factors of teenage childbearing among Ethiopian women using semi-parametric and parametric proportional hazard and accelerated failure time models

BACKGROUND

Teenage childbearing is a common issue for young people's sexual and reproductive health in the world, particularly in low-income countries, and affects teenagers between the ages of 13 and 19. According to several academics, adolescent pregnancy accounts for the majority of Ethiopia's population increase, and there has been little effort to address this threat. This study aimed to determine the prevalence and associated factors of the time to teenage childbearing in Ethiopia.

METHOD

This paper compares the results of the semi-parametric proportional hazard (PH), parametric PH, and accelerated failure time (AFT) models to find the model that best fits the data. The Akaike Information Criterion (AIC) was used to evaluate the performance of models examined in this investigation. Time to teenage childbearing was the study's outcome variable, while the analysis considered various independent variables. We analyze data from the 2016 National Demographic Health Survey to assess the influence of different risk factors on teenage pregnancy among Ethiopian women.

RESULTS

Out of the 10,274 teenagers (aged between 13 and 19) who participated in the 2016 survey, 6,430 (62.59%) were parents. The study findings revealed that these teenage parents were influenced by various time-related factors before becoming parents. The log-normal AFT model has the lowest AIC value and hence it is the best fit for this data. Results from this model indicated that significant factors influencing the time to teenage childbearing include the age of the household head, current age of the respondents, region, religion, educational attainment, wealth status, intention to use contraception, and recent sexual activity.

CONCLUSION

This study reveals that 62.59% of surveyed teenagers aged 13 to 19 were parents. Various factors at both the individual and community levels: including the age of the household head, regional differences, religious affiliation, educational level, economic status, contraceptive intentions, and recent sexual activity, determine the time to teenage childbearing. Targeted interventions addressing these factors are essential for reducing teenage pregnancies and supporting adolescent parents effectively.

Reduced probability of improving viro-immunological state in subjects with vertical transmission of HIV reaching adult age: A multicenter retrospective cohort study

INTRODUCTION

Young adults with vertical transmission (VT) of human immunodeficiency virus (HIV) represent a fragile population. This study evaluates factors associated with viro-immunological outcome of these patients.

METHODS

We performed a multicenter study including HIV-infected subjects with VT ≥ 18 years old from six Italian clinics. Subjects were observed from birth to death, lost to follow-up, or last visit until December 31, 2019. Condition of "optimal viro-immunological status" (OS) was defined as the simultaneous presence of HIV ribonucleic acid (RNA) < 50 copies/mL, CD4+ > 500 cells/mm³ , and CD4+/CD8+ ratio ≥ 1.

RESULTS

A total of 126 subjects were enrolled. At 18 years of age, 52/126 (44.4%) had HIV-RNA > 50 copies/mL, 47/126 (38.2%) had CD4+ < 500/mm³ , and 78/126 (67.2%) had CD4+/CD8+ < 1; 28 subjects (23.7%) presented in the condition of OS. Having a CD4+/CD8+ ratio ≥ 1 at 18 years of age was related with an increased probability of shift from suboptimal viro-immunological status (SOS) to OS (HR: 7.7, 95% confidence interval [CI]: 4.23-14.04), and a reduced risk of shift from the OS to the SOS (HR: 0.49, 95% CI: 0.26-0.92). Acquired immunodeficiency syndrome (AIDS) diagnosis significantly reduced the probability of shift from a viro-immunological SOS to OS (HR: 0.09, 95% CI: 0.03-0.30). Subjects who had not achieved an OS at 18 years of age had an increased risk of discontinuation of combination antiretroviral therapy (cART, p = .019).

CONCLUSIONS

Only a small proportion of subjects with VT of HIV reached the adult age with "OS". Transition to the adult care with a compromised viro-immunological condition represents a negative driver for future optimal infection control, with a higher risk of discontinuation of cART and a reduced probability to improve the immunological status later in the years.

Modelling HIV disease process and progression in seroconversion among South Africa women: using transition-specific parametric multi-state model

BACKGROUND

HIV infected patients may experience many intermediate events including between-event transition throughout their follow up. Through modelling these transitions, we can gain a deeper understanding of HIV disease process and progression and of factors that influence the disease process and progression pathway. In this work, we present transition-specific parametric multi-state models to describe HIV disease process and progression.

METHODS

The data is from an ongoing prospective cohort study conducted amongst adult women who were HIV-infected in KwaZulu-Natal, South Africa. Participants were enrolled during the acute HIV infection phase and then followed up during chronic infection, up to ART initiation.

RESULTS

Transition specific distributions for multi-state models, including a variety of accelerated failure time (AFT) models and proportional hazards (PH) models, were presented and compared in this study. The analysis revealed that women enrolling with a CD4 count less than 350 cells/mm3 (severe and advanced disease stages) had a far lower chance of immune recovery, and a considerably higher chance of immune deterioration, compared to women enrolling with a CD4 count of 350 cells/mm3 or more (normal and mild disease stages). Our analyses also showed that older age, higher educational levels, higher scores for red blood cell counts, higher mononuclear scores, higher granulocytes scores, and higher physical health scores, all had a significant effect on a shortened time to immunological recovery, while women with many sex partners, higher viral load and larger family size had a significant effect on accelerating time to immune deterioration.

CONCLUSION

Multi-state modelling of transition-specific distributions offers a flexible tool for the study of demographic and clinical characteristics' effects on the entire disease progression pathway. It is hoped that the article will help applied researchers to familiarize themselves with the models, including interpretation of results.

Multilevel ordinal model for CD4 count trends in seroconversion among South Africa women

BACKGROUND

Ordinal health longitudinal response variables have distributions that make them unsuitable for many popular statistical models that assume normality. We present a multilevel growth model that may be more suitable for medical ordinal longitudinal outcomes than are statistical models that assume normality and continuous measurements.

METHODS

The data is from an ongoing prospective cohort study conducted amongst adult women who are HIV-infected patients in Kwazulu-Natal, South Africa. Participants were enrolled into the acute infection, then into early infection subsequently into established infection and afterward on cART. Generalized linear multilevel models were applied.

RESULTS

Multilevel ordinal non-proportional and proportional-odds growth models were presented and compared. We observed that the effects of covariates can't be assumed identical across the three cumulative logits. Our analyses also revealed that the rate of change of immune recovery of patients increased as the follow-up time increases. Patients with stable sexual partners, middle-aged, cART initiation, and higher educational levels were more likely to have better immunological stages with time. Similarly, patients having high electrolytes component scores, higher red blood cell indices scores, higher physical health scores, higher psychological well-being scores, a higher level of independence scores, and lower viral load more likely to have better immunological stages through the follow-up time.

CONCLUSION

It can be concluded that the multilevel non-proportional-odds method provides a flexible modeling alternative when the proportional-odds assumption of equal effects of the predictor variables at every stage of the response variable is violated. Having higher clinical parameter scores, higher QoL scores, higher educational levels, and stable sexual partners were found to be the significant factors for trends of CD4 count recovery.