Pre-exposure prophylaxis for individuals who are at high risk for HIV infection has been shown to be effective at preventing infection. The authors of this article aimed to investigate whether ‘on-demand’ pre-exposure prophylaxis is also cost effective, specifically in Canada in a population of men who have sex with men, who are at higher risk for HIV infection. The authors used multiple methods to generate a thorough cost-effectiveness analysis that has implications for the use of this therapy in Canada.

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PurposeHigh-dimensional propensity scores (hdPS) can adjust for measured confounders, but it remains unclear how well it can adjust for unmeasured confounders. Our goal was to identify if the hdPS method could adjust for confounders which were hidden to the hdPS algorithm.MethodThe hdPS algorithm was used to estimate two hdPS; the first version (hdPS-1) was estimated using data provided by 6 data dimensions and the second version (hdPS-2) was estimated using data provided from only two of the 6 data dimensions. Two matched sub-cohorts were created by matching one patient initiated on a high-dose statin to one patient initiated on a low-dose statin based on either hdPS-1 (Matched hdPS Full Info Sub-Cohort) or hdPS-2 (Matched hdPS Hidden Info Sub-Cohort). Performances of both hdPS were compared by means of the absolute standardized differences (ASDD) regarding 18 characteristics (data on seven of the 18 characteristics were hidden to the hdPS algorithm when estimating the hdPS-2).ResultsEight out of the 18 characteristics were shown to be unbalanced within the unmatched cohort. Matching on either hdPS achieved adequate balance (i.e., ASDD <0.1) on all 18 characteristics.ConclusionOur results indicate that the hdPS method was able to adjust for hidden confounders supporting the claim that the hdPS method can adjust for at least some unmeasured confounders.

Within the limitations of this study, there is a suggestion that bariatric surgery has a major impact on mobility and HRQoL. More research is warranted to understand the benefits, costs, and cost-effectiveness of bariatric surgery in Canada.

BackgroundComparative performance of the traditional propensity score (PS) and high-dimensional propensity score (hdPS) methods in the adjustment for confounding by indication remains unclear. We aimed to identify which method provided the best adjustment for confounding by indication within the context of the risk of diabetes among patients exposed to moderate versus high potency statins.MethodA cohort of diabetes-free incident statins users was identified from the Quebec’s publicly funded medico-administrative database (Full Cohort). We created two matched sub-cohorts by matching one patient initiated on a lower potency to one patient initiated on a high potency either on patients’ PS or hdPS. Both methods’ performance were compared by means of the absolute standardized differences (ASDD) regarding relevant characteristics and by means of the obtained measures of association.ResultsEight out of the 18 examined characteristics were shown to be unbalanced within the Full Cohort. Although matching on either method achieved balance within all examined characteristic, matching on patients’ hdPS created the most balanced sub-cohort. Measures of associations and confidence intervals obtained within the two matched sub-cohorts overlapped.ConclusionAlthough ASDD suggest better matching with hdPS than with PS, measures of association were almost identical when adjusted for either method. Use of the hdPS method in adjusting for confounding by indication within future studies should be recommended due to its ability to identify confounding variables which may be unknown to the investigators.Electronic supplementary materialThe online version of this article (doi:10.1186/s12874-016-0119-1) contains supplementary material, which is available to authorized users.

BackgroundThe number of frail elderly will increase as the world population ageing accelerates. Since frail elders are at risk of falls, hospitalizations and disabilities, they will require more health care and services. To assess frailty prevalence using health administrative databases, to examine the association between frailty and the use of medical services and to measure the excess use of health services following a non-hip fracture across frailty levels among community-dwelling seniors.MethodsA population-based cohort study was built from the Quebec Integrated Chronic Disease Surveillance System, including men and women ≥65 years old, non-institutionalized in the pre-fracture year. Frailty was measured using the Elders Risk Assessment (ERA) index. Multivariate Generalized Estimating Equation models were used to examine the relationship between frailty levels and health services while adjusting for covariates. The excess numbers of visits to Emergency Departments (ED) and to Primary Care Practitioners (PCP) as well as hospitalizations were also estimated.ResultsThe cohort included 178,304 fractures. There were 13.6 and 5.2% frail and robust seniors, respectively. In the post-fracture year, the risks of ED visits, PCP visits and hospitalizations, were significantly higher in frail vs. non-frail seniors: adjusted relative risk (RR) = 2.69 [95% CI: 2.50–2.90] for ED visits, RR = 1.28 [95% CI: 1.23–1.32] for PCP visits and RR = 2.34 [95% CI: 2.14–2.55] for hospitalizations.ConclusionOur results suggest that it is possible to characterize seniors’ frailty status at a population level using health administrative databases. Furthermore, this study shows that non-institutionalized frail seniors require more health services after an incident fracture. Screening for frailty in seniors should be part of clinical management in order to identify those at a higher risk of needing health services.Electronic supplementary materialThe online version of this article (10.1186/s12913-019-3865-z) contains supplementary material, which is available to authorized users.

The growth of healthcare spending is a major concern for insurers and governments but also for patients whose health problems may result in costs going beyond direct medical costs. To develop a comprehensive tool to measure direct and indirect costs of a health condition for patients and their families to various outpatient contexts.Methods: We conducted a content and face validation including results of a systematic review to identify the items related to direct and indirect costs for patients or their families and an online Delphi to determine the cost items to retain. We conducted a pilot test-retest with 18 naive participants and analyzed data calculating intraclass correlation and kappa coefficients.Results: An initial list of 34 items was established from the systematic review. Each round of the Delphi panel incorporated feedback from the previous round until a strong consensus was achieved. After 4 rounds of the Delphi to reach consensus on items to be included and wording, the questionnaire had a total of 32 cost items. For the test-retest, kappa coefficients ranged from 20.11 to 1.00 (median = 0.86), and intraclass correlation ranged from 20.02 to 0.99 (median = 0.62).Conclusions: A rigorous process of content and face development was implemented for the Cost for Patients Questionnaire, and this study allowed to set a list of cost elements to be considered from the patient's perspective. Additional research including a test-retest with a larger sample will be part of a subsequent validation strategy.

BackgroundStatins are the mainstay hypercholesterolemia treatment and reduce the risk of cardiovascular events in patients. However, statin therapy is often interrupted in patients experiencing musculoskeletal pain or myopathy, which are common in this patient group. Currently, the standard tests for diagnosing statin myopathies are difficult to interpret. A pharmacogenomics (PGx) test to diagnose statin-induced myopathy would be highly desirable.MethodsWe developed a Markov state model to assess the cost-effectiveness of a hypothetical PGx test, which aims to identify statin-induced myopathy in high-risk, secondary prevention cardiovascular patients. The alternative strategy hypothesized is that physicians or patients interrupt the statin therapy in the presence of musculoskeletal pain. Our model includes health states specific to the PGx test outcome which assesses the impact of test errors.ResultsAssuming a perfect test, the results indicate that the PGx test strategy dominates when the test costs less than CAN$356, when the strategy is cost neutral. These results are robust to deterministic and probabilistic sensitivity analyses.ConclusionOur base-case results show that a PGx test for statin-induced myopathy in a high-risk, secondary prevention of a cardiovascular event population would be a dominant solution for a test cost of CAN$356 or less. Furthermore, the modelling of the complete range of diagnostic test outcomes provide a broader understanding of the economic value of the pharmacogenomics test.