The impact of proposed price regulations on new patented medicine launches in Canada: a retrospective cohort study.

BACKGROUND: The Patented Medicine Prices Review Board (PMPRB), the agency that regulates the prices of patented medicines in Canada, published proposed amendments to the regulatory framework in December 2017. Because of a series of changes and delays, the revised policy has not yet been finalized. We sought to evaluate the potential early impact of the uncertainty about the PMPRB policy on patented-medicine launches. METHODS: We developed a retrospective cohort of patented medicines (molecules) sold in Canada and the 13 countries that the PMPRB currently uses or has proposed to use as price comparators, from sales data from the IQVIA MIDAS database for 2012-2021. The outcome was whether a molecule was launched (i.e., sold) in a specific country within 2 years of its global first launch (2-yr launch). We compared the change of 2-year launch before (2012-2017) and after the proposed amendments were published ("uncertain period," 2018-2021) in Canada with the change in the United States and the other 12 countries as a group ("other-countries group"), using interrupted time series and logistic regressions, respectively. We further conducted analyses for each individual country and subgroups by molecule characteristics, such as therapeutic benefit, separately. RESULTS: We included 242 and 107 new molecules launched before publication of the proposed amendments and during the uncertain period, respectively. The corresponding 2-year launch proportions were 45.0% and 30.8% in Canada, 81.4% and 82.2% in the US, and 83.9% and 70.1% in the other-countries group. All analyses showed changes in 2-year launch during the uncertain period in the US and in the other-countries group that were similar to the changes in Canada. Greater decreases were observed in Norway and Sweden than in Canada. The 2-year launch proportion for molecules with major therapeutic benefit decreased from 45.8% to 31.3% in Canada during the uncertain period and from 87.5% to 62.5% in the other-countries group, but increased from 91.7% to 100% in the US. INTERPRETATION: No negative impact of the PMPRB-policy uncertainty on molecule launches was observed when comparing Canada with price-comparator countries, except for molecules with major therapeutic benefit. The reduction in launches of medicines with major therapeutic benefit in Canada requires continuing investigation.

People With Human Immunodeficiency Virus Receiving Suppressive Antiretroviral Therapy Show Typical Antibody Durability After Dual Coronavirus Disease 2019 Vaccination and Strong Third Dose Responses.

BACKGROUND: Longer-term humoral responses to 2-dose coronavirus disease 2019 (COVID-19) vaccines remain incompletely characterized in people living with human immunodeficiency virus (HIV) (PLWH), as do initial responses to a third dose. METHODS: We measured antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein receptor-binding domain, angiotensin-converting enzyme 2 (ACE2) displacement, and viral neutralization against wild-type and Omicron strains up to 6 months after 2-dose vaccination, and 1 month after the third dose, in 99 PLWH receiving suppressive antiretroviral therapy and 152 controls. RESULTS: Although humoral responses naturally decline after 2-dose vaccination, we found no evidence of lower antibody concentrations or faster rates of antibody decline in PLWH compared with controls after accounting for sociodemographic, health, and vaccine-related factors. We also found no evidence of poorer viral neutralization in PLWH after 2 doses, nor evidence that a low nadir CD4+ T-cell count compromised responses. Post-third-dose humoral responses substantially exceeded post-second-dose levels, though Omicron-specific responses were consistently weaker than responses against wild-type virus. Nevertheless, post-third-dose responses in PLWH were comparable to or higher than controls. An mRNA-1273 third dose was the strongest consistent correlate of higher post-third-dose responses. CONCLUSION: PLWH receiving suppressive antiretroviral therapy mount strong antibody responses after 2- and 3-dose COVID-19 vaccination. Results underscore the immune benefits of third doses in light of Omicron.

Modeling Tiered Pricing Frameworks: A Simulation Approach.

OBJECTIVE: Drug plans take different approaches to determining reimbursement prices for generic drugs. One common approach is to set the maximum reimbursement price as a percentage of the price of the interchangeable branded drug. In many countries this percentage depends on the number of generic entrants, a model we call "tiered pricing." This paper seeks to enhance understanding of how to set the tiers. METHODS: We construct a simple model of tiered pricing and set parameters to match evidence on generic drug costs and the distribution of revenues. Using simulation methods, we then assess different tier structures in terms of total surplus and average drug cost. RESULTS: We find when tiers are bunched tightly together welfare outcomes are poor. Moreover, there are large welfare gains from increasing the number of tiers from one to two, and only small welfare gains from increasing the number of tiers beyond four. CONCLUSIONS: The choice of tiers has substantial welfare and cost implications. While it is possible to refine the simulation analysis based on specific market characteristics, an optimal tier structure, such as the one we propose in the paper, should have at least two tiers.

Understanding COVID-19 Vaccine Confidence in People Living with HIV: A pan-Canadian Survey.

Understanding the roots of Covid-19 vaccine hesitancy in at-risk groups, such as persons living with HIV (PLWH), is of utmost importance. We developed a modified Vaccine Hesitancy Scale (VHS) questionnaire using items from the National Advisory Committee on Immunization Acceptability Matrix. To examine factors associated with receiving COVID-19 vaccine and the link between vaccine attitudes and beliefs with vaccine behavior, PLWH were recruited via social media and community-based organizations (February-May 2022). Descriptive statistics were used to summarize results. Total VHS score was generated by adding Likert scale scores and linear regression models used to compare results between participants who received or did not receive COVID-19 vaccines. Logistic regression models were used to identify factors associated with vaccine uptake. A total of 246 PLWH indicated whether they received a COVID-19 vaccine. 89% received ≥ 1 dose. Mean total VHS(SD) for persons having received ≥ 1 COVID-19 vaccine was 17.8(6.2) vs. 35.4(9.4) for participants not having received any COVID-19 vaccine. Persons who received ≥ 1 dose were significantly older than those who had not received any (48.4 ± 13.8 vs. 34.0 ± 7.7 years, p < 0.0001). The majority of participants considered COVID-19 vaccination important for their health(81.3%) and the health of others(84.4%). Multivariate logistic regression revealed the odds of taking ≥ 1dose were increased 2.4-fold [95% CI 1.6, 3.5] with each increase in age of 10 years (p < 0.0001). Sex and ethnicity were not different between groups. In conclusion, PLWH accept COVID-19 vaccines for both altruistic and individual reasons. With evolving recommendations and increasing numbers of booster vaccines, we must re-examine the needs of PLWH regularly.

Patient-reported mental health and well-being trajectories in oncology patients during radiation therapy: an exploratory retrospective cohort analysis using the Ontario Cancer Registry.

PURPOSE: Mental health and well-being trajectories are not expected to be homogeneous in diverse clinical populations. This exploratory study aims to identify subgroups of patients with cancer receiving radiation therapy who have different mental health and well-being trajectories, and examine which socio-demographic, physical symptoms, and clinical variables are associated with such trajectories. METHODS: Retrospective analysis of radiation therapy patients diagnosed with cancer in 2017 was conducted using data from the Ontario Cancer Registry (Canada) and linked with administrative health data. Mental health and well-being were measured using items from the Edmonton Symptom Assessment System-revised questionnaire. Patients completed up to 6 repeated measurements. We used latent class growth mixture models to identify heterogeneous mental health trajectories of anxiety, depression, and well-being. Bivariate multinomial logistic regressions were conducted to explore variables associated with the latent classes (subgroups). RESULTS: The cohort (N = 3416) with a mean age of 64.5 years consisted of 51.7% females. Respiratory cancer was the most common diagnosis (30.4%) with moderate to severe comorbidity burden. Four latent classes with distinct anxiety, depression, and well-being trajectories were identified. Decreasing mental health and well-being trajectories are associated with being female; living in neighborhoods with lower income, greater population density, and higher proportion of foreign-born individuals; and having higher comorbidity burden. CONCLUSIONS: The findings highlight the importance of considering social determinants of mental health and well-being, in addition to symptoms and clinical variables, when providing care for patients undergoing radiation therapy.

Preventative behaviours and COVID-19 infection in a Canadian cohort of people living with HIV.

Few studies have examined preventative behaviour practices with respect to COVID-19 among people living with HIV (human immunodeficiency virus). Using a cross-sectional survey from a Canadian Institutes of Health Research Canadian HIV Trials Network study (CTN 328) of people living with HIV on vaccine immunogenicity, we examined the relationships between participant characteristics and behavioural practices intended to prevent COVID-19 infection. Participants living in four Canadian urban centers were enrolled between April 2021-January 2022, at which time they responded to a questionnaire on preventative behaviour practices. Questionnaire and clinical data were combined to explore relationships between preventive behaviours and (1) known COVID-19 infection pre-enrolment, (2) multimorbidity, (3) developing symptomatic COVID-19 infection, and (4) developing symptomatic COVID-19 infection during the Omicron wave. Among 375 participants, 49 had COVID-19 infection pre-enrolment and 88 post-enrolment. The proportion of participants reporting always engaging in preventative behaviours included 87% masking, 79% physical distancing, 70% limiting social gatherings, 65% limiting contact with at-risk individuals, 33% self-isolating due to symptoms, and 26% self-quarantining after possible exposure. Participants with known COVID-19 infection pre-enrolment were more likely to self-quarantine after possible exposure although asymptomatic (65.0% vs 23.4%, p < 0.001; Chi-square test). Participants with multiple comorbidities more likely endorsed physical distancing (85.7% vs 75.5%, p = 0.044; Chi-square test), although this was not significant in logistic regression analysis adjusted for age, sex, race, number of household members, number of bedrooms/bathrooms in the household per person, influenza immunization, and working in close physical proximity to others. Overall, participants reported frequent practice of preventative behaviours.

Comparing the use of aggregate data and various methods of integrating individual patient data to network meta-analysis and its application to first-line ART.

BACKGROUND: The 2018 World Health Organization HIV guidelines were based on the results of a network meta-analysis (NMA) of published trials. This study employed individual patient-level data (IPD) and aggregate data (AgD) and meta-regression methods to assess the evidence supporting the WHO recommendations and whether they needed any refinements. METHODS: Access to IPD from three trials was granted through ClinicalStudyDataRequest.com (CSDR). Seven modelling approaches were applied and compared: 1) Unadjusted AgD network meta-analysis (NMA) - the original analysis; 2) AgD-NMA with meta-regression; 3) Two-stage IPD-AgD NMA; 4) Unadjusted one-stage IPD-AgD NMA; 5) One-stage IPD-AgD NMA with meta-regression (one-stage approach); 6) Two-stage IPD-AgD NMA with empirical-priors (empirical-priors approach); 7) Hierarchical meta-regression IPD-AgD NMA (HMR approach). The first two were the models used previously. Models were compared with respect to effect estimates, changes in the effect estimates, coefficient estimates, DIC and model fit, rankings and between-study heterogeneity. RESULTS: IPD were available for 2160 patients, representing 6.5% of the evidence base and 3 of 24 edges. The aspect of the model affected by the choice of modeling appeared to differ across outcomes. HMR consistently generated larger intervals, often with credible intervals (CrI) containing the null value. Discontinuations due to adverse events and viral suppression at 96 weeks were the only two outcomes for which the unadjusted AgD NMA would not be selected. For the first, the selected model shifted the principal comparison of interest from an odds ratio of 0.28 (95% CrI: 10.17, 0.44) to 0.37 (95% CrI: 0.23, 0.58). Throughout all outcomes, the regression estimates differed substantially between AgD and IPD methods, with the latter being more often larger in magnitude and statistically significant. CONCLUSIONS: Overall, the use of IPD often impacted the coefficient estimates, but not sufficiently as to necessitate altering the final recommendations of the 2018 WHO Guidelines. Future work should examine the features of a network where adjustments will have an impact, such as how much IPD is required in a given size of network.

Health-care practitioners' preferences for the return of secondary findings from next-generation sequencing: a discrete choice experiment.

PURPOSE: Health-care practitioners' (HCPs) preferences for returning secondary findings (SFs) will influence guideline compliance, shared decision-making, and patient health outcomes. This study aimed to estimate HCPs' preferences and willingness to support the return (WTSR) of SFs in Canada. METHODS: A discrete choice experiment estimated HCPs' preferences for the following attributes: disease risk, clinical utility, health consequences, prior experience, and patient preference. We analyzed responses with an error component mixed logit model and predicted WTSR using scenario analyses. RESULTS: Two hundred fifty participants of 583 completed the questionnaire (completion rate: 42.9%). WTSR was significantly influenced by patient preference and SF outcome characteristics. HCPs' WTSR was 78% (95% confidence interval: 74-81%) when returning SFs with available medical treatment, high penetrance, severe health consequences, and patient's preference for return. Genetics professionals had a higher WTSR than HCPs of other types when returning SFs with clinical utility and patient preference to know. HCPs >55 years of age were more likely to return SFs compared with younger HCPs. CONCLUSION: This study identified factors that influence WTSR of SFs and indicates that HCPs make tradeoffs between patient preference and other outcome characteristics. The results can inform clinical scenarios and models aiming to understand shared decision-making, patient and family opportunity to benefit, and cost-effectiveness.

Triple Therapy Versus Biologic Therapy for Active Rheumatoid Arthritis: A Cost-Effectiveness Analysis.

Background: The RACAT (Rheumatoid Arthritis Comparison of Active Therapies) trial found triple therapy to be noninferior to etanercept-methotrexate in patients with active rheumatoid arthritis (RA). Objective: To determine the cost-effectiveness of etanercept-methotrexate versus triple therapy as a first-line strategy. Design: A within-trial analysis based on the 353 participants in the RACAT trial and a lifetime analysis that extrapolated costs and outcomes by using a decision analytic cohort model. Data Sources: The RACAT trial and sources from the literature. Target Population: Patients with active RA despite at least 12 weeks of methotrexate therapy. Time Horizon: 24 weeks and lifetime. Perspective: Societal and Medicare. Intervention: Etanercept-methotrexate first versus triple therapy first. Outcome Measures: Incremental costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). Results of Base-Case Analysis: The within-trial analysis found that etanercept-methotrexate as first-line therapy provided marginally more QALYs but accumulated substantially higher drug costs. Differences in other costs between strategies were negligible. The ICERs for first-line etanercept-methotrexate and triple therapy were $2.7 million per QALY and $0.98 million per QALY over 24 and 48 weeks, respectively. The lifetime analysis suggested that first-line etanercept-methotrexate would result in 0.15 additional lifetime QALY, but this gain would cost an incremental $77 290, leading to an ICER of $521 520 per QALY per patient. Results of Sensitivity Analysis: Considering a long-term perspective, an initial strategy of etanercept-methotrexate and biologics with similar cost and efficacy is unlikely to be cost-effective compared with using triple therapy first, even under optimistic assumptions. Limitation: Data on the long-term benefit of triple therapy are uncertain. Conclusion: Initiating biologic therapy without trying triple therapy first increases costs while providing minimal incremental benefit. Primary Funding Source: The Cooperative Studies Program, Department of Veterans Affairs Office of Research and Development, Canadian Institutes for Health Research, and an interagency agreement with the National Institutes of Health-American Recovery and Reinvestment Act.

A Practical ANOVA Approach for Uncertainty Analysis in Population-Based Disease Microsimulation Models.

OBJECTIVES: To provide a practical approach for calculating uncertainty intervals and variance components associated with initial-condition and dynamic-equation parameters in computationally expensive population-based disease microsimulation models. METHODS: In the proposed uncertainty analysis approach, we calculated the required computational time and the number of runs given a user-defined error bound on the variance of the grand mean. The equations for optimal sample sizes were derived by minimizing the variance of the grand mean using initial estimates for variance components. Finally, analysis of variance estimators were used to calculate unbiased variance estimates. RESULTS: To illustrate the proposed approach, we performed uncertainty analysis to estimate the uncertainty associated with total direct cost of osteoarthritis in Canada from 2010 to 2031 according to a previously published population health microsimulation model of osteoarthritis. We first calculated crude estimates for initial-population sampling and dynamic-equation parameters uncertainty by performing a small number of runs. We then calculated the optimal sample sizes and finally derived 95% uncertainty intervals of the total cost and unbiased estimates for variance components. According to our results, the contribution of dynamic-equation parameter uncertainty to the overall variance was higher than that of initial parameter sampling uncertainty throughout the study period. CONCLUSIONS: The proposed analysis of variance approach provides the uncertainty intervals for the mean outcome in addition to unbiased estimates for each source of uncertainty. The contributions of each source of uncertainty can then be compared with each other for validation purposes so as to improve the model accuracy.

Do Biologic Therapies for Rheumatoid Arthritis Offset Treatment-Related Resource Utilization and Cost? A Review of the Literature and an Instrumental Variable Analysis.

PURPOSE OF REVIEW: One justification for using expensive biologic therapy in rheumatoid arthritis (RA) has been that it can reduce future healthcare utilization such as joint surgeries and physician visits. However, the evidence to support this assertion is unclear. We conducted a review of the literature for studies which have analyzed the trends in resource use of RA patients, and then undertook a retrospective observational analysis of a Canadian administrative database using instrumental variable methods. RECENT FINDINGS: Our review found a trend in reduced resource utilization prior to the introduction of biologics and no evidence that biologic therapies have specifically contributed to this reduction. Our observational analysis, which overcame some of the epidemiological challenges with determining the influence of biologics on resource utilization, found a possible reduction in other medications but possible increases rather than decreases in physician visits and hospitalizations. However, our sample was not sufficiently large to make definitive conclusions. Over 15 years since the introduction of biologics for RA, no evidence exists supporting the assumption that biologic therapies reduce future healthcare utilization. While such a question is challenging to generate evidence for, and so an absence of evidence does not suggest that the hypothesis is incorrect, an instrumental variable analysis using sufficient data could provide definitive evidence.

Therapies for active rheumatoid arthritis after methotrexate failure.

BACKGROUND: Few blinded trials have compared conventional therapy consisting of a combination of disease-modifying antirheumatic drugs with biologic agents in patients with rheumatoid arthritis who have active disease despite treatment with methotrexate--a common scenario in the management of rheumatoid arthritis. METHODS: We conducted a 48-week, double-blind, noninferiority trial in which we randomly assigned 353 participants with rheumatoid arthritis who had active disease despite methotrexate therapy to a triple regimen of disease-modifying antirheumatic drugs (methotrexate, sulfasalazine, and hydroxychloroquine) or etanercept plus methotrexate. Patients who did not have an improvement at 24 weeks according to a prespecified threshold were switched in a blinded fashion to the other therapy. The primary outcome was improvement in the Disease Activity Score for 28-joint counts (DAS28, with scores ranging from 2 to 10 and higher scores indicating more disease activity) at week 48. RESULTS: Both groups had significant improvement over the course of the first 24 weeks (P=0.001 for the comparison with baseline). A total of 27% of participants in each group required a switch in treatment at 24 weeks. Participants in both groups who switched therapies had improvement after switching (P<0.001), and the response after switching did not differ significantly between the two groups (P=0.08). The change between baseline and 48 weeks in the DAS28 was similar in the two groups (-2.1 with triple therapy and -2.3 with etanercept and methotrexate, P=0.26); triple therapy was noninferior to etanercept and methotrexate, since the 95% upper confidence limit of 0.41 for the difference in change in DAS28 was below the margin for noninferiority of 0.6 (P=0.002). There were no significant between-group differences in secondary outcomes, including radiographic progression, pain, and health-related quality of life, or in major adverse events associated with the medications. CONCLUSIONS: With respect to clinical benefit, triple therapy, with sulfasalazine and hydroxychloroquine added to methotrexate, was noninferior to etanercept plus methotrexate in patients with rheumatoid arthritis who had active disease despite methotrexate therapy. (Funded by the Cooperative Studies Program, Department of Veterans Affairs Office of Research and Development, and others; CSP 551 RACAT ClinicalTrials.gov number, NCT00405275.)

The Impact of Price-cap Regulations on Exit by Generic Pharmaceutical Firms.

BACKGROUND: In 1998, the Province of Ontario in Canada adopted price-cap "70/90" regulations whereby the first generic entrant was required to be priced at ≤70% of the associated brand-name product and subsequent generics were priced at ≤90% of the first generic price. The price-caps were further lowered to 50% in 2006 and 25% in 2010. This study assessed the impact of such price-cap regulations on exit by generic drug firms. METHODS: Formulary (2003-2012) listings of prescription drugs covered under the Ontario Drug Benefit program were used. The formulary tracks the "status" (on formulary, discontinued by manufacturer, and delisted for other reasons) for each drug. Markets were defined based on unique active ingredient and form within Ontario. Firm exit occurred when a manufacturer discontinued all its generic drugs within a market. The exit rate was defined as the number of generic firm-market exits divided by total generic firm-market follow-up years. Poisson regression was used to compare the exit rates during the 3 policy periods ("25," "50," and "70/90"). RESULTS: A total of 1126 generic manufacturers paired with 290 markets were identified. The exit rate ratio during the 25% price-cap period compared with the 70%/90% period was 2.42 (95% confidence interval, 1.56-3.77). A small manufacturer or a manufacturer in a market with ≥3 competitors or in an older market was more likely to exit. CONCLUSIONS: Lowering the price-cap level is associated with a higher incidence of generic firm exit from markets. Continuously reducing price-caps may have the unintended consequence of forcing generic firms to exit.

Incentives in Rheumatology: the Potential Contribution of Physician Responses to Financial Incentives, Public Reporting, and Treatment Guidelines to Health Care Sustainability.

Concerns about the sustainability of current health care expenditure are focusing attention on the cost, quality and value of health care provision. Financial incentives, for example pay-for-performance (P4P), seek to reward quality and value in health care provision. There has long been an expectation that P4P schemes are coming to rheumatology. We review the available evidence about the use of incentives in this setting and provide two emerging examples of P4P schemes which may shape the future of service provision in rheumatology. Currently, there is limited and equivocal evidence in rheumatology about the impact of incentive schemes. However, reporting variation in the quality and provision of rheumatology services has highlighted examples of inefficiencies in the delivery of care. If financial incentives can improve the delivery of timely and appropriate care for rheumatology patients, then they may have an important role to play in the sustainability of health care provision.

Long-term (10-year) mortality of younger previously healthy patients with severe sepsis/septic shock is worse than that of patients with nonseptic critical illness and of the general population.

OBJECTIVES: Long-term (1- to 10-year) outcomes after severe sepsis in previously healthy persons are unknown. We aimed to determine the 1- to 10-year mortality rates of previously healthy patients with severe sepsis and compare these to mortality rates of patients with nonseptic critical illness and the general population. DESIGN: A prospective cohort study of 2,289 patients from one mixed medical-surgical ICU and one cardiovascular surgery ICU. Age- and gender-comparable general British Columbia population was used as comparison. Patients were followed from the date of admission to the ICU to January 31, 2013. Provincial vital statistics were used to determine the patients' date of death. For the general population comparison, expected survival was obtained from life tables of the population of British Columbia, Canada. SETTING: A quaternary-level provincial referral hospital in Vancouver, British Columbia, Canada. PATIENTS: Two thousand two hundred eighty-nine patients from one mixed medical-surgical ICU and one cardiovascular surgery ICU. Age- and gender-comparable general British Columbia population was used for comparison. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients with severe sepsis without comorbidities had higher mortality from 1 to 10 years than general British Columbia population (p < 0.01). Younger patients with severe sepsis (< 60 yr) had the worst 1- to 5-year and 5- to 10-year mortality (hazard ratio [95% CI], 17.8 [13.4-24.8] and 6.0 [4-9]) compared with the general population. Patients with severe sepsis had significantly poorer 1- to 10-year mortality rates (30.5%) compared with patients with nonseptic critical illness (22.1%) and patients who have undergone cardiovascular surgery (15.9%). Patients with sepsis had higher mortality rates from 1-5 years and 5-10 years than the general British Columbia population (hazard ratio [95% CI], 4.5 [2.2-9.1] and 2.2 [0.9-14.7]). CONCLUSIONS: Previously healthy patients suffering an episode of severe sepsis have increased long-term mortality compared with patients with nonseptic critical illness and a general population.

High levels of opioid analgesic co-prescription among methadone maintenance treatment clients in British Columbia, Canada: results from a population-level retrospective cohort study.

BACKGROUND AND OBJECTIVES: The non-medical use of prescription opioids (PO) has increased dramatically in North America. Special consideration for PO prescription is required for individuals in methadone maintenance treatment (MMT). Our objective is to describe the prevalence and correlates of PO use among British Columbia (BC) MMT clients from 1996 to 2007. METHODS: This study was based on a linked, population-level medication dispensation database. All individuals receiving 30 days of continuous MMT for opioid dependence were included in the study. Key measurements included the proportion of clients receiving >7 days of a PO other than methadone during MMT from 1996 to 2007. Factors independently associated with PO co-prescription during MMT were assessed using generalized linear mixed effects regression. RESULTS: 16,248 individuals with 27,919 MMT episodes at least 30 days in duration were identified for the study period. Among them, 5,552 individuals (34.2%) received a total of 290,543 PO co-prescriptions during MMT. The majority (74.3%) of all PO dispensations >7 days originated from non-MMT physicians. The number of PO prescriptions per person-year nearly doubled between 1996 and 2006, driven by increases in morphine, hydromorphone and oxycodone dispensations. PO co-prescription was positively associated with female gender, older age, higher levels of medical co-morbidity as well as higher MMT dosage, adherence, and retention. CONCLUSION AND SCIENTIFIC SIGNIFICANCE: A large proportion of MMT clients in BC received co-occurring PO prescriptions, often from physicians and pharmacies not delivering MMT. Experimental evidence for the treatment of pain in MMT clients is required to guide clinical practice.

The impact of changing the reference countries on the list prices for patented medicines in Canada: A policy analysis.

BACKGROUND: Canada's Patented Medicine Prices Review Board (PMPRB) uses external and internal reference pricing (IRP) to regulate patented drug list prices. PMPRB has changed external reference countries from 7 to 11 to include countries with prices closer to the OECD median. We examined the impact on the list prices for patented medicines had the amendment been implemented from 2013. METHODS: Using IQVIA MIDAS® quarterly sales data, we selected branded products that were launched in Canada in 2013-2018. The list price for each product in each country was calculated as its average annual price during the 3rd year post Canadian launch. The median international price (MIP) was the median of the list prices of PMPRB7 (MIP7) and PMPRB11 (MIP11). We assumed the same IRP would be (scenario 1) or would not be used (scenario 2). RESULTS: Among the selected 400 products, 80.3 % (321) had MIP7 and MIP11 (launched in at least one reference country); 18.3 % did not have MIP11. The total current expenditures were $7,134.4 M. In scenario 1, MIP11 would not be binding for most products and expenditures would decline only by 0.7 %. If IRP were abolished, expenditures might decline by 14.1 % if the launching sequence would not change. CONCLUSIONS: MIP11 might not be binding for most medicines. The impact depends on whether to retain the IRP and approaches taken for medicines without MIP11.

Correlates of Breakthrough SARS-CoV-2 Infections in People with HIV: Results from the CIHR CTN 328 Study.

COVID-19 breakthrough infection (BTI) can occur despite vaccination. Using a multi-centre, prospective, observational Canadian cohort of people with HIV (PWH) receiving ≥2 COVID-19 vaccines, we compared the SARS-CoV-2 spike (S) and receptor-binding domain (RBD)-specific IgG levels 3 and 6 months post second dose, as well as 1 month post third dose, in PWH with and without BTI. BTI was defined as positivity based on self-report measures (data up to last study visit) or IgG data (up to 1 month post dose 3). The self-report measures were based on their symptoms and either a positive PCR or rapid antigen test. The analysis was restricted to persons without previous COVID-19 infection. Persons without BTI remained COVID-19-naïve until ≥3 months following the third dose. Of 289 participants, 92 developed BTI (31.5 infections per 100 person-years). The median days between last vaccination and BTI was 128 (IQR 67, 176), with the most cases occurring between the third and fourth dose (n = 59), corresponding to the Omicron wave. In analyses adjusted for age, sex, race, multimorbidity, hypertension, chronic kidney disease, diabetes and obesity, a lower IgG S/RBD (log10 BAU/mL) at 1 month post dose 3 was significantly associated with BTI, suggesting that a lower IgG level at this time point may predict BTI in this cohort of PWH.

Factors associated with pretreatment and treatment dropouts: comparisons between Aboriginal and non-Aboriginal clients admitted to medical withdrawal management.

BACKGROUND: Addiction treatment faces high pretreatment and treatment dropout rates, especially among Aboriginals. In this study we examined characteristic differences between Aboriginal and non-Aboriginal clients accessing an inpatient medical withdrawal management program, and identified risk factors associated with the probabilities of pretreatment and treatment dropouts, respectively. METHODS: 2231 unique clients (Aboriginal = 451; 20%) referred to Vancouver Detox over a two-year period were assessed. For both Aboriginal and non-Aboriginal groups, multivariate logistic regression analyses were conducted with pretreatment dropout and treatment dropout as dependent variables, respectively. RESULTS: Aboriginal clients had higher pretreatment and treatment dropout rates compared to non-Aboriginal clients (41.0% vs. 32.7% and 25.9% vs. 20.0%, respectively). For Aboriginal people, no fixed address (NFA) was the only predictor of pretreatment dropout. For treatment dropout, significant predictors were: being female, having HCV infection, and being discharged on welfare check issue days or weekends. For non-Aboriginal clients, being male, NFA, alcohol as a preferred substance, and being on methadone maintenance treatment (MMT) at referral were associated with pretreatment dropout. Significant risk factors for treatment dropout were: being younger, having a preferred substance other than alcohol, having opiates as a preferred substance, and being discharged on weekends. CONCLUSIONS: Our results highlight the importance of social factors for the Aboriginal population compared to substance-specific factors for the non-Aboriginal population. These findings should help clinicians and decision-makers to recognize the importance of social supports especially housing and initiate appropriate services to improve treatment intake and subsequent retention, physical and mental health outcomes and the cost-effectiveness of treatment.

Risk of COVID-19 hospitalization in people living with HIV and HIV-negative individuals and the role of COVID-19 vaccination: A retrospective cohort study.

OBJECTIVE: To examine the risk of hospitalization within 14 days of COVID-19 diagnosis among people living with HIV (PLWH) and HIV-negative individuals who had laboratory-confirmed SARS-CoV-2 infection. METHODS: We used Cox proportional hazard models to compare the relative risk of hospitalization in PLWH and HIV-negative individuals. Then, we used propensity score weighting to examine the influence of sociodemographic factors and comorbid conditions on risk of hospitalization. These models were further stratified by vaccination status and pandemic period (pre-Omicron: December 15, 2020, to November 21, 2021; Omicron: November 22, 2021, to October 31, 2022). RESULTS: The crude hazard ratio (HR) for risk of hospitalization in PLWH was 2.44 (95% confidence interval [CI]: 2.04-2.94). In propensity score-weighted models that included all covariates, the relative risk of hospitalization was substantially attenuated in the overall analyses (adjusted HR [aHR]: 1.03; 95% CI: 0.85-1.25), in vaccinated (aHR 1.00; 95% CI: 0.69-1.45), inadequately vaccinated (aHR: 1.04; 95% CI: 0.76-1.41) and unvaccinated individuals (aHR: 1.15; 95% CI: 0.84-1.56). CONCLUSION: PLWH had about two times the risk of COVID-19 hospitalization than HIV-negative individuals in crude analyses which attenuated in propensity score-weighted models. This suggests that the risk differential can be explained by sociodemographic factors and history of comorbidity, underscoring the need to address social and comorbid vulnerabilities (e.g., injecting drugs) that were more prominent among PLWH.