Healthcare utilisation and costs associated with adherence to antipsychotics among people living with HIV/AIDS and schizophrenia: a population-based cohort study in British Columbia, Canada

OBJECTIVES

Non-adherence to antipsychotics is the greatest obstacle to treating schizophrenia. We assessed the economic and clinical impacts of adherence to antipsychotics among people living with HIV/AIDS (PLWH) and schizophrenia in British Columbia, Canada.

DESIGN AND SETTING

A population-based cohort study in British Columbia, Canada.

METHODS

Eligible PLWH were enrolled in the Seek and Treat for Optimal Prevention HIV/AIDS population-based cohort during 2001-2016, diagnosed with schizophrenia, on antipsychotics for ≥1 day, and followed for ≥1 year from schizophrenia diagnosis date or 1 January 2001, whichever occurred last.

PRIMARY AND SECONDARY OUTCOME MEASURES

A two-part model assessed the marginal effect of adherence on healthcare costs (in 2016 Canadian dollar), while logistic regression examined the effect on virological failure, and generalised linear mixed models examined the effect on hospital readmissions within 30 days and length of hospital stay.

RESULTS

Among 726 PLWH with schizophrenia, ≥80% adherence to antipsychotics increased from 25% (50/198) in 2001 to 41% (225/554) in 2016. In most years, we observed no difference in adherence to antipsychotics among those who used only injectables, only non-injectables, and a combination of both, or among those who have ever consumed typical/first-generation antipsychotics and who consumed only atypical/second-generation antipsychotics. Overall healthcare costs were higher in the non-adherent group ($C2185), driven by the average annual hospitalisation costs ($C5517), particularly among women ($C8806) and people who ever injected drugs (PWID) ($C5985). Non-adherent individuals also experienced higher hospital readmissions (adjusted odds ratio (aOR) 1.48, 95% CI 1.23 to 1.77), and longer hospital stays (adjusted mean ratio 1.23, 95% CI 1.13 to 1.35) in comparison to adherent individuals. We found no difference in virological failure by adherence groups, except when we stratified by gender where the aOR for women was 2.48 (95% CI 1.06 to 5.82).

CONCLUSIONS

Our results showed that implementing strategies and interventions to increase antipsychotic adherence, particularly among women and PWID, will be critical in addressing this public health challenge.

Disability-adjusted life years associated with chronic comorbidities among people living with and without HIV: Estimating health burden in British Columbia, Canada

Life span of people living with HIV (PLWH) has increased dramatically with the advent of modern antiretroviral therapy. As a result, comorbidities have emerged as a significant concern in this population. To describe the burden of chronic comorbidities among PLWH and HIV-negative individuals in British Columbia (BC), Canada, we estimated disability-adjusted life years (DALYs) related to these comorbidities. Based on a population-based cohort in BC, antiretroviral-treated adult PLWH and 1:4 age-sex-matched HIV-negative controls were followed for ≥1 year during 2001-2012. DALYs combined years of life lost to premature mortality (YLLs) and due to disability (YLDs), and were estimated following the Global Burden of Diseases' approaches. DALYs associated with non-AIDS-defining cancers, diabetes, osteoarthritis, hypertension, dementia, cardiovascular (CVD), kidney, liver and chronic obstructive pulmonary diseases were each measured for 2008-2012. Among PLWH, DALYs attributed to non-AIDS-related cancers were also estimated for 2013-2020. We observed that at baseline, our matched cohort consisted of 82% males with a median age of 40 years (25th-75th percentiles: 34-47). During 2008-2012, 7042 PLWH and 30,640 HIV-negative individuals were alive, where PLWH experienced a twofold higher DALYs associated with chronic comorbidities (770.2 years/1000 people [95% credible intervals: 710.2, 831.6] vs. 359.0 [336.0, 382.2]). Non-AIDS-defining cancers and CVD contributed the highest DALYs in both populations, driven by YLLs rather than YLDs. Among PLWH, we estimated increasing DALYs attributable to non-AIDS-defining cancers with 91.7 years/1000 people (77.4, 106.0) in 2013 vs. 97.6 (81.0, 115.2) in 2020. In this study, we showed that PLWH experience a disproportionate burden of chronic comorbidities compared to HIV-negative individuals. The observed disparities may relate to differential health behaviors, residual HIV-related inflammation, and ART-related toxicities. As aging shapes future healthcare needs, our findings highlight the need to enhance prevention and management of comorbidities as part of HIV care.

Use of Gay Chatlines and Online Dating Platforms as Potential Mediators or Moderators in the Relationship Between Loneliness, Self-Rated Attractiveness and Human Immunodeficiency Virus Acquisition Risk Among Gay, Bisexual, and Other Men Who Have Sex With Men in Vancouver, Canada

BACKGROUND

Gay, bisexual, and other men who have sex with men (gbMSM) remain disproportionately affected by human immunodeficiency virus (HIV). Interaction between psychosocial factors likely plays a role in HIV acquisition risk. We aimed to analyze the association of loneliness and self-rated attractiveness with HIV acquisition risk, and determine whether these associations were mediated by gay telephone chatlines or online dating platforms.

METHODS

This cross-sectional study included HIV-negative gbMSM 16 years or older enrolled into the Momentum Health Study from February 2012 to February 2015. Loneliness, self-rated attractiveness (exposures) and use of gay chatlines or online dating platforms (mediators) were assessed through self-interviews. Human immunodeficiency virus acquisition risk (outcome) was assessed by the HIV Incidence Risk Index. Weighted logistic regression modeled the association and moderation effect between exposures and outcome. Mediation models estimated 3-way direct effect among exposures, mediators, and outcome.

RESULTS

Of 542 gbMSM, those who were lonely (adjusted odds ratio [aOR], 1.54; 95% confidence intervals [CI], 1.04-2.28) and attractive (aOR, 1.69; 95% CI, 1.04-2.76) had increased odds for HIV acquisition risk. Our moderation analysis demonstrated a heightened joint effect among lonely and attractive participants (aOR, 1.70; 95% CI, 1.08-2.65). Use of gay telephone chatlines or online dating platforms mediated 30.5% of the association between loneliness and HIV acquisition risk, but did not mediate attractiveness and HIV acquisition risk.

CONCLUSIONS

Our findings suggest that the provision of interventions focusing on mental health support and safer sex practices through gay telephone chatlines or online dating platforms is promising to help alleviate the HIV burden among gbMSM.

The impact of lookback windows on the prevalence and incidence of chronic diseases among people living with HIV: an exploration in administrative health data in Canada

BACKGROUND

We described the impact of different lengths of lookback window (LW), a retrospective time period to observe diagnoses in administrative data, on the prevalence and incidence of eight chronic diseases.

METHODS

Our study populations included people living with HIV (N = 5151) and 1:5 age-sex-matched HIV-negative individuals (N = 25,755) in British Columbia, Canada, with complete follow-up between 1996 and 2012. We measured period prevalence and incidence of diseases in 2012 using LWs ranging from 1 to 16 years. Cases were deemed prevalent if identified in 2012 or within a defined LW, and incident if newly identified in 2012 with no previous cases detected within a defined LW. Chronic disease cases were ascertained using published case-finding algorithms applied to population-based provincial administrative health datasets.

RESULTS

Overall, using cases identified by the full 16-year LW as the reference, LWs ≥8 years and ≥ 4 years reduced the proportion of misclassified prevalent and incidence cases of most diseases to < 20%, respectively. The impact of LWs varied across diseases and populations.

CONCLUSIONS

This study underscored the importance of carefully choosing LWs and demonstrated data-driven approaches that may inform these choices. To improve comparability of prevalence and incidence estimates across different settings, we recommend transparent reporting of the rationale and limitations of chosen LWs.

A province-wide HIV initiative to accelerate initiation of treatment-as-prevention and virologic suppression in British Columbia, Canada: a population-based cohort study

BACKGROUND

In 2010, HIV treatment as prevention (TasP), encompassing widespread HIV testing and immediate initiation of free antiretroviral treatment (ART), was piloted under the Seek and Treat for Optimal Prevention of HIV/AIDS initiative (STOP) in British Columbia, Canada. We compared the time from HIV diagnosis to treatment initiation, and from treatment initiation to first virologic suppression, before (2005-2009) and after (2010-2016) the implementation of STOP.

METHODS

In this population-based cohort study, we used longitudinal data of all people living with an HIV diagnosis in BC from 1996 to 2017. We included those aged 18 years or older who had never received ART and had received an HIV diagnosis in the 2005-2016 period. We defined the virologic suppression date as the first date of at least 2 consecutive test results within 4 months with a viral load of less than 200 copies/mL. Negative binomial regression models assessed the effect of STOP on the time to ART initiation and suppression, adjusting for confounders. All p values were 2-sided, and we set the significance level at 0.05.

RESULTS

Participants who received an HIV diagnosis before STOP (n = 1601) were statistically different from those with a diagnosis after STOP (n = 1700); 81% versus 84% were men (p = 0.0187), 30% versus 15% had ever injected drugs (p < 0.0001), and 27% versus 49% had 350 CD4 cells/μL or more at diagnosis (p < 0.0001). The STOP initiative was associated with a 64% shorter time from diagnosis to treatment (adjusted mean ratio 0.36, 95% confidence interval [CI] 0.34-0.39) and a 21% shorter time from treatment to suppression (adjusted mean ratio 0.79, 95% CI 0.73-0.85).

INTERPRETATION

In a population with universal health coverage, a TasP intervention was associated with shorter times from HIV diagnosis to treatment initiation, and from treatment initiation to viral suppression. Our results show accelerating progress toward the United Nations' 90-90-90 target of people with HIV who have a diagnosis, those who are on antiretroviral therapy and those who are virologically suppressed, and support the global expansion of TasP to accelerate the control of HIV/AIDS.

Disparities in multimorbidity and mortality among people living with and without HIV across British Columbia's health regions: a population-based cohort study

OBJECTIVES

Longer survival has increased the likelihood of antiretroviral-treated people living with HIV (PLWH) developing age-associated comorbidities. We compared the burden of multimorbidity and all-cause mortality across HIV status in British Columbia (BC), and assessed the longitudinal effect of multimorbidity on all-cause mortality among PLWH.

METHODS

Antiretroviral-treated PLWH aged ≥19 years and 1:4 age-sex-matched HIV-negative individuals from a population-based cohort were followed for ≥1 year during 2001-2012. Diagnoses of seven age-associated comorbidities were identified from provincial administrative databases and grouped into 0, 1, 2, and ≥3 comorbidities. Multimorbidity prevalence and age-standardized mortality rates (ASMRs) in both populations were stratified by BC's health regions. Marginal structural models were used to estimate the effect of multimorbidity on mortality among PLWH, adjusted for time-varying confounders affected by prior multimorbidity.

RESULTS

Among 8031 PLWH and 32,124 HIV-negative individuals, 25% versus 11% developed multimorbidity, and 23.53 deaths/1000 person-years (95% confidence interval [95% CI]: 22.02-25.13) versus 3.04 (2.81-3.29) were observed, respectively. PLWH in Northern region had the highest ASMR, but those in South Vancouver Island experienced the greatest difference in mortality compared with HIV-negative individuals. Among PLWH, compared with those with zero comorbidities, adjusted hazard ratios for those with 1, 2, and ≥3 comorbidities were 3.36 (95% CI: 2.86-3.95), 6.92 (5.75-8.33), and 12.87 (10.45-15.85), respectively.

CONCLUSION

PLWH across BC's health regions experience excess multimorbidity and associated mortality. We highlight health disparities which are key when planning the distribution of healthcare resources across BC, and provide evidence for improved HIV care models integrating prevention and management of chronic diseases.

Current and Past Immunodeficiency Are Associated With Higher Hospitalization Rates Among Persons on Virologically Suppressive Antiretroviral Therapy for up to 11 Years

BACKGROUND

Persons with human immunodeficiency virus (PWH) with persistently low CD4 counts despite efficacious antiretroviral therapy could have higher hospitalization risk.

METHODS

In 6 US and Canadian clinical cohorts, PWH with virologic suppression for ≥1 year in 2005-2015 were followed until virologic failure, loss to follow-up, death, or study end. Stratified by early (years 2-5) and long-term (years 6-11) suppression and lowest presuppression CD4 count <200 and ≥200 cells/µL, Poisson regression models estimated hospitalization incidence rate ratios (aIRRs) comparing patients by time-updated CD4 count category, adjusted for cohort, age, gender, calendar year, suppression duration, and lowest presuppression CD4 count.

RESULTS

The 6997 included patients (19 980 person-years) were 81% cisgender men and 40% white. Among patients with lowest presuppression CD4 count <200 cells/μL (44%), patients with current CD4 count 200-350 vs >500 cells/μL had aIRRs of 1.44 during early suppression (95% confidence interval [CI], 1.01-2.06), and 1.67 (95% CI, 1.03-2.72) during long-term suppression. Among patients with lowest presuppression CD4 count ≥200 (56%), patients with current CD4 351-500 vs >500 cells/μL had an aIRR of 1.22 (95% CI, .93-1.60) during early suppression and 2.09 (95% CI, 1.18-3.70) during long-term suppression.

CONCLUSIONS

Virologically suppressed patients with lower CD4 counts experienced higher hospitalization rates and could potentially benefit from targeted clinical management strategies.

Racial, ethnic, and gender disparities in hospitalizations among persons with HIV in the United States and Canada, 2005-2015

OBJECTIVE

To examine recent trends and differences in all-cause and cause-specific hospitalization rates by race, ethnicity, and gender among persons with HIV (PWH) in the United States and Canada.

DESIGN

HIV clinical cohort consortium.

METHODS

We followed PWH at least 18 years old in care 2005-2015 in six clinical cohorts. We used modified Clinical Classifications Software to categorize hospital discharge diagnoses. Incidence rate ratios (IRR) were estimated using Poisson regression with robust variances to compare racial and ethnic groups, stratified by gender, adjusted for cohort, calendar year, injection drug use history, and annually updated age, CD4+, and HIV viral load.

RESULTS

Among 27 085 patients (122 566 person-years), 80% were cisgender men, 1% transgender, 43% White, 33% Black, 17% Hispanic of any race, and 1% Indigenous. Unadjusted all-cause hospitalization rates were higher for Black [IRR 1.46, 95% confidence interval (CI) 1.32-1.61] and Indigenous (1.99, 1.44-2.74) versus White cisgender men, and for Indigenous versus White cisgender women (2.55, 1.68-3.89). Unadjusted AIDS-related hospitalization rates were also higher for Black, Hispanic, and Indigenous versus White cisgender men (all P < 0.05). Transgender patients had 1.50 times (1.05-2.14) and cisgender women 1.37 times (1.26-1.48) the unadjusted hospitalization rate of cisgender men. In adjusted analyses, among both cisgender men and women, Black patients had higher rates of cardiovascular and renal/genitourinary hospitalizations compared to Whites (all P < 0.05).

CONCLUSION

Black, Hispanic, Indigenous, women, and transgender PWH in the United States and Canada experienced substantially higher hospitalization rates than White patients and cisgender men, respectively. Disparities likely have several causes, including differences in virologic suppression and chronic conditions such as diabetes and renal disease.

Incidence of diabetes mellitus among people living with and without HIV in British Columbia, Canada between 2001 and 2013: a longitudinal population-based cohort study

INTRODUCTION

People living with HIV (PLHIV) are increasingly at risk of age-related comorbidities such as diabetes mellitus (DM). While DM is associated with elevated mortality and morbidity, understanding of DM among PLHIV is limited. We assessed the incidence of DM among people living with and without HIV in British Columbia (BC), Canada, during 2001-2013.

METHODS

We used longitudinal data from a population-based cohort study linking clinical data and administrative health data. We included PLHIV who were antiretroviral therapy (ART) naïve at baseline, and 1:5 age-sex-matched persons without HIV. All participants had ≥5 years of historic data pre-baseline and ≥1 year(s) of follow-up. DM was identified using the BC Ministry of Health's definitions applied to hospitalisation, physician billing and drug dispensation datasets. Incident DM was identified using a 5-year run-in period. In addition to unadjusted incidence rates (IRs), we estimated adjusted incidence rate ratios (IRR) using Poisson regression and assessed annual trends in DM IRs per 1000 person years (PYs) between 2001 and 2013.

RESULTS

A total of 129 PLHIV and 636 individuals without HIV developed DM over 17 529 PYs and 88,672 PYs, respectively. The unadjusted IRs of DM per 1000 PYs were 7.4 (95% CI 6.2 to 8.8) among PLHIV and 7.2 (95% CI 6.6 to 7.8) for individuals without HIV. After adjustment for confounding, HIV serostatus was not associated with DM incidence (adjusted IRR: 1.03, 95% CI 0.83 to 1.27). DM incidence did not increase over time among PLHIV (Kendall trend test: p=0.9369), but it increased among persons without HIV between 2001 and 2013 (p=0.0136).

CONCLUSIONS

After adjustment, HIV serostatus was not associated with incidence of DM, between 2001 and 2013. Future studies should investigate the impact of ART on mitigating the potential risk of DM among PLHIV.

Excess burden of age-associated comorbidities among people living with HIV in British Columbia, Canada: a population-based cohort study

OBJECTIVES

As people living with HIV (PLWH) live longer, morbidity and mortality from non-AIDS comorbidities have emerged as major concerns. Our objective was to compare prevalence trends and age at diagnosis of nine chronic age-associated comorbidities between individuals living with and without HIV.

DESIGN AND SETTING

This population-based cohort study used longitudinal cohort data from all diagnosed antiretroviral-treated PLWH and 1:4 age-sex-matched HIV-negative individuals in British Columbia, Canada.

PARTICIPANTS

The study included 8031 antiretroviral-treated PLWH and 32 124 HIV-negative controls (median age 40 years, 82% men). Eligible participants were ≥19 years old and followed for ≥1 year during 2000 to 2012.

PRIMARY AND SECONDARY OUTCOME MEASURES

The presence of non-AIDS-defining cancers, diabetes, osteoarthritis, hypertension, Alzheimer's and/or non-HIV-related dementia, cardiovascular, kidney, liver and lung diseases were identified from provincial administrative databases. Beta regression assessed annual age-sex-standardised prevalence trends and Kruskal-Wallis tests compared the age at diagnosis of comorbidities stratified by rate of healthcare encounters.

RESULTS

Across study period, the prevalence of all chronic age-associated comorbidities, except hypertension, were higher among PLWH compared with their community-based HIV-negative counterparts; as much as 10 times higher for liver diseases (25.3% vs 2.1%, p value<0.0001). On stratification by healthcare encounter rates, PLWH experienced most chronic age-associated significantly earlier than HIV-negative controls, as early as 21 years earlier for Alzheimer's and/or dementia.

CONCLUSIONS

PLWH experienced higher prevalence and earlier age at diagnosis of non-AIDS comorbidities than their HIV-negative controls. These results stress the need for optimised screening for comorbidities at earlier ages among PLWH, and a comprehensive HIV care model that integrates prevention and treatment of chronic age-associated conditions. Additionally, the robust methodology developed in this study, which addresses concerns on the use of administrative health data to measure prevalence and incidence, is reproducible to other settings.

Hospitalization Rates and Causes Among Persons With HIV in the United States and Canada, 2005-2015

BACKGROUND

To assess the possible impact of antiretroviral therapy improvements, aging, and comorbidities, we examined trends in all-cause and cause-specific hospitalization rates among persons with HIV (PWH) from 2005 to 2015.

METHODS

In 6 clinical cohorts, we followed PWH in care (≥1 outpatient CD4 count or HIV load [VL] every 12 months) and categorized ICD codes of primary discharge diagnoses using modified Clinical Classifications Software. Poisson regression estimated hospitalization rate ratios for calendar time trends, adjusted for demographics, HIV risk factor, and annually updated age, CD4, and VL.

RESULTS

Among 28 057 patients (125 724 person-years), from 2005 to 2015, the median CD4 increased from 389 to 580 cells/µL and virologic suppression from 55% to 85% of patients. Unadjusted all-cause hospitalization rates decreased from 22.3 per 100 person-years in 2005 (95% confidence interval [CI], 20.6-24.1) to 13.0 in 2015 (95% CI, 12.2-14.0). Unadjusted rates decreased for almost all diagnostic categories. Adjusted rates decreased for all-cause, cardiovascular, and AIDS-defining conditions, increased for non-AIDS-defining infection, and were stable for most other categories.

CONCLUSIONS

Among PWH with increasing CD4 counts and viral suppression, unadjusted hospitalization rates decreased for all-cause and most cause-specific hospitalizations, despite the potential effects of aging, comorbidities, and cumulative exposure to HIV and antiretrovirals.

Missed opportunities for earlier diagnosis of HIV in British Columbia, Canada: A retrospective cohort study

BACKGROUND

Late HIV diagnosis is associated with increased AIDS-related morbidity and mortality as well as an increased risk of HIV transmission. In this study, we quantified and characterized missed opportunities for earlier HIV diagnosis in British Columbia (BC), Canada.

DESIGN

Retrospective cohort.

METHODS

A missed opportunity was defined as a healthcare encounter due to a clinical manifestation which may be caused by HIV infection, or is frequently present among those with HIV infection, but no HIV diagnosis followed within 30 days. We developed an algorithm to identify missed opportunities within one, three, and five years prior to diagnosis. The algorithm was applied to the BC STOP HIV/AIDS population-based cohort. Eligible individuals were ≥18 years old, and diagnosed from 2001-2014. Multivariable logistic regression identified factors associated with missed opportunities.

RESULTS

Of 2119 individuals, 7%, 12% and 14% had ≥1 missed opportunity during one, three and five years prior to HIV diagnosis, respectively. In all analyses, individuals aged ≥40 years, heterosexuals or people who ever injected drugs, and those residing in Northern health authority had increased odds of experiencing ≥1 missed opportunity. In the three and five-year analysis, individuals with a CD4 count <350 cells/mm3 were at higher odds of experiencing ≥1 missed opportunity. Prominent missed opportunities were related to recurrent pneumonia, herpes zoster/shingles among younger individuals, and anemia related to nutritional deficiencies or unspecified cause.

CONCLUSIONS

Based on our newly-developed algorithm, this study demonstrated that HIV-diagnosed individuals in BC have experienced several missed opportunities for earlier diagnosis. Specific clinical indicator conditions and population sub-groups at increased risk of experiencing these missed opportunities were identified. Further work is required in order to validate the utility of this proposed algorithm by establishing the sensitivity, specificity, positive and negative predictive values corresponding to the incidence of the clinical indicator conditions among both HIV-diagnosed and HIV-negative populations.