Factors partitioning physical frailty in people aging with HIV: A classification and regression tree approach.

OBJECTIVE: To estimate the extent to which comorbidity and lifestyle factors were associated with physical frailty in middle-aged and older Canadians living with HIV. DESIGN: Cross-sectional analysis of 856 participants from the Canadian Positive Brain Health Now cohort. METHODS: The frailty indicator phenotype was adapted from Fried's criteria using self-report items. Univariate logistic regression and classification and regression tree (CaRT) models were used to identify the most relevant independent contributors to frailty. RESULTS: In all, 100 men (14.0%) and 26 women (19.7%) were identified as frail (≥ 3/5 criteria) for an overall prevalence of 15.2%. Nine comorbidities showed an influential association with frailty. The most influential comorbidities were hypothyroidism [odds ratio (OR) = 2.55, 95% confidence interval (CI): 1.29-5.03] and arthritis (OR = 2.54, 95% CI: 1.58-4.09). Additionally, tobacco (OR = 1.79, 95% CI: 1.05-3.04) showed an association. Any level of alcohol consumption showed a protective effect for frailty. The CaRT model showed nine pathways that led to frailty. Arthritis was the most discriminatory variable followed by alcohol, hypothyroidism, tobacco, cancer, cannabis, liver disease, kidney disease, osteoporosis, lung disease and peripheral vascular disease. The prevalence of physical frailty for people with arthritis was 27.4%; with additional cancer or tobacco and alcohol the prevalence rates were 47.1% and 46.1%, respectively. The protective effect of alcohol consumption evident in the univariate model appeared again in the CaRT model, but this effect varied. Cognitive frailty (19.5% overall) and emotional frailty (37.9% overall) were higher than the prevalence of physical frailty. CONCLUSIONS: Specific comorbidities and tobacco use were implicated in frailty, suggesting that it is comorbidities causing frailty. However, some frailty still appears to be HIV-related. The higher prevalence of cognitive and emotional frailty highlights the fact that physical frailty should not be the only focus in HIV.

A better screening tool for HIV-associated neurocognitive disorders: is it what clinicians need?

OBJECTIVE: Existing screening tools for HIV-Associated Neurocognitive Disorders (HAND) may lack the accuracy required for clinical use. We hypothesized that the diagnostic accuracy of the Montreal Cognitive Assessment (MoCA) as a screening tool for HAND might be improved with a stronger scoring methodology. DESIGN: Two hundred HIV-positive participants aged 18-65 years completed the MoCA and a battery of neuropsychological tests. METHODS: HAND diagnosis was established according to the Frascati criteria, and an NPZ-8 score was also calculated. Rasch analysis was applied to the MoCA items to create a quantitative score. RESULTS: The optimal cut-off on the quantitative MoCA for detecting impairment as per Frascati criteria yielded a sensitivity of 0.74 and a specificity of 0.68. Overall accuracy was 0.79 (95% CI: 0.73-0.85), an improvement over standard scoring methods. However, whether cognition was quantified with the quantitative MoCA or with NPZ-8, there was substantial overlap between diagnostic categories; several individuals categorized as impaired had better overall cognitive function as assessed by NPZ-8 or quantitative MoCA than those classified as normal using standard criteria. CONCLUSION: Quantifying performance on MoCA items through Rasch analysis improves its accuracy as a screening tool for HAND, and demonstrates that cognition can be measured as a unidimensional construct in HIV, at least at the level of precision of bedside testing. However, the current categorical diagnostic approach to HAND is poorly aligned with summary measures of cognitive ability. Measuring cognition as a quasi-continuous construct may be more relevant than conventional HAND diagnostic categories for many clinical purposes.