Publications by authors named "Daphne P Guh"

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.

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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.

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Background: The current prostate cancer (PCa) screening standard of care (SOC) leads to unnecessary biopsies and overtreatment because decisions are guided by prostate-specific antigen (PSA) levels, which have low specificity in the gray zone (3-10 ng/mL). New risk assessment tools (RATs) aim to improve biopsy decision-making. We constructed a modeling framework to assess new RATs in men with gray zone PSA from the British Columbia healthcare system's perspective.

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We aimed to estimate the total health care costs attributable to prostate cancer (PCa) during care phases by age, cancer stage, tumor grade, and primary treatment in the first year in British Columbia (BC), Canada. Using linked administrative health data, we followed a cohort of men aged ≥ 50 years at diagnosis with PCa between 2010 and 2017 (Cohort 1) from the diagnosis date until the date of death, the last date of observation, or 31 December 2019. Patients who died from PCa after 1 January 2010, were selected for Cohort 2.

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Background: Generic drug prices have been capped at specified percentages of the interchangeable branded drug's price by the Canadian provincial public drug plans since 1993. The Pan-Canadian Pharmaceutical Alliance, formed as a coalition by the provinces/territories in Canada, implemented an alternative approach, a tiered-pricing framework (TPF) for new generic drugs on April 1, 2014, under which the percentage varies with the number of generic firms in each market. We evaluate the impact of the TPF on generic entry, ie, listing in public drug plans in Canada.

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Article Synopsis
  • Health Canada has been tracking drug shortages since 2017 by requiring manufacturers to report them, with a study aimed at understanding the factors leading to these shortages in Canada.
  • An analysis of 3,470 prescription drug markets showed that 13.3% faced shortages, especially those with only one generic producer or specific dosage forms.
  • The findings suggest that government monitoring should focus on markets at risk, particularly those with single producers, complex manufacturing needs, high public demand, or certain classifications related to sensory organs.
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Background: Although diacetylmorphine has been proven to be more effective than methadone maintenance treatment for opioid dependence, its direct costs are higher. We compared the cost-effectiveness of diacetylmorphine and methadone maintenance treatment for chronic opioid dependence refractory to treatment.

Methods: We constructed a semi-Markov cohort model using data from the North American Opiate Medication Initiative trial, supplemented with administrative data for the province of British Columbia and other published data, to capture the chronic, recurrent nature of opioid dependence.

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Background: While opioid substitution treatment (OST) provides the opportunity for substantial improvements in health related quality of life (HRQoL), this relationship is seldom documented and poorly understood. Our objectives were to identify differences in trajectories of HRQoL among chronic opioid-dependent patients and factors associated with improvement and deterioration in HRQoL following enrolment in opioid substitution treatment.

Methods: In the North American Opiate Medication Initiative (NAOMI) randomized controlled trial, the Euroqol (EQ-5D) and other measures of demographic, health and drug use characteristics were collected at baseline and quarterly follow-up.

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Dropout and recidivism from addiction treatment has been found to be associated with individuals' readiness for change. Motivation for treatment among participants entering the North American Opiate Medication Initiative (NAOMI) randomized controlled trial, which compared heroin assisted treatment (HAT) to optimized methadone maintenance treatment (MMT), was assessed. Through multivariate regression, we aimed to determine whether baseline motivational status was predictive of four treatment outcomes: early dropout, 12-month retention, 12-month response to treatment, and time to discontinuation of treatment.

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Objective: To provide a comparative analysis of the psychometric properties of eight measures of health status among chronic opioid-dependent patients.

Study Design And Setting: Longitudinal data were analyzed for 251 patients enrolled in the North American Opiate Medication Initiative randomized controlled trial, conducted in Vancouver, British Columbia and Montreal, Quebec, Canada. Content validity, evidence of floor and ceiling effects, internal consistency, construct validity, and responsiveness were assessed for the Addiction Severity Index (ASI) medical and psychiatric (ASImed and ASIpsych) composite scores, the Maudesley Addiction Profile (MAP) physical and mental health scores (MAP-physical health score [MAP-PHS], MAP-mental health score [MAP-MHS]), the World Health Organization Disability Assessment Schedule-II, the EuroQol Group's EQ-5D index score and visual analog scale, EuroQol visual analog scale (EQ-VAS), and the Short Form SF-6D index score.

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Objectives: To assess the concurrent validity and responsiveness of the Health Utility Index 3 (HUI3) in patients with advanced HIV/AIDS, and to determine the responsiveness of this measure, the MOS-HIV and EQ-5D to HIV-related clinical events.

Methods: Data from the OPTIMA (OPTions In Management with Antiretrovirals) trial was analyzed. Two aspects of the validity of the HUI3 were considered: concurrent validity was evaluated using Spearman correlations with MOS-HIV component and summary scores.

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Objective: To investigate the relative magnitude and duration of impact of AIDS-defining events (ADEs) and non-AIDS serious adverse events (SAEs) on health-related quality of life (HRQoL) among patients with advanced HIV/AIDS.

Methods: We use data from OPTIMA (OPTions In Management with Antiretrovirals), a multinational, randomized, open, control, clinical management trial of treatment strategies for patients with multidrug-resistant HIV and advanced immune disease. Longitudinal models were used to determine the effects of ADEs and SAEs on HRQoL across periods before, during, and after event onset.

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Background: Overweight and obese persons are at risk of a number of medical conditions which can lead to further morbidity and mortality. The primary objective of this study is to provide an estimate of the incidence of each co-morbidity related to obesity and overweight using a meta-analysis.

Methods: A literature search for the twenty co-morbidities identified in a preliminary search was conducted in Medline and Embase (Jan 2007).

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Objective: Rheumatoid arthritis (RA) is associated with increased frequency of and mortality from infections, which may be related to host factors, RA itself, inflammation, or medication side effects. This study was undertaken to determine the effect of nonbiologic disease-modifying antirheumatic drugs (DMARDs) on infection risk in RA.

Methods: We performed a retrospective, longitudinal study of a population-based RA cohort in British Columbia, Canada, followed from January 1996 to March 2003 using administrative data.

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The impact of healthcare interventions on health utility values is most frequently measured using a preference-based instrument. Each of the available instruments instructs the respondent to report their health status over different recall periods ranging from the current day to the past month. In an ongoing randomised controlled trial in patients with advanced HIV disease, the impact of using a preference-based instrument with a 1-week recall period vs a 1-day recall period (e.

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Background: Previous research has shown that patient cost-sharing leads to a reduction in overall health resource utilization. However, in Canada, where health care is provided free of charge except for prescription drugs, the converse may be true. We investigated the effect of prescription drug cost-sharing on overall health care utilization among elderly patients with rheumatoid arthritis.

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Objective: Treatment guidelines for rheumatoid arthritis (RA) now recommend early, aggressive, and persistent use of disease-modifying antirheumatic drugs (DMARDs) to prevent joint damage in all people with active inflammation, and evaluation by a rheumatologist, when possible. This research assesses whether care for RA, at a population level, is consistent with current treatment guidelines.

Methods: Using administrative billing data from the Ministry of Health in 1996-2000, all prevalent RA cases in British Columbia, Canada were identified.

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Background: Leaving the hospital against medical advice has been associated with increased morbidity and readmission. Factors associated with the risk of leaving against medical advice among HIV/AIDS patients or injection drug users have not been examined in detail.

Objectives: To examine the clinical and social factors associated with leaving against medical advice (AMA) from a specialized HIV/AIDS ward among patients who reported a history of injection drug use.

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Background: In Ontario, Canada, the 70/90 regulations were instituted in May 1993 to establish provincial government procurement prices for generic drugs. Accordingly, the first generic entrant's price could not exceed 70% of the incumbent's branded price. Subsequent entrants' prices could not exceed 90% of the first entrant's price.

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Article Synopsis
  • The study aimed to evaluate asthma management trends in British Columbia and explore factors linked to increased use of short-acting beta-agonists (SA) from 1996 to 1998.
  • Researchers analyzed data from 78,758 patients who received SA beta-agonist prescriptions and found no decline in their annual use despite asthma management guidelines.
  • Notable findings included an increase in patients not using inhaled corticosteroids and that males, those over 18, and recipients of social assistance were more likely to use higher amounts of SA beta-agonists.
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Background: Hospital discharge against medical advice, especially among substance-abusing populations, is a frustrating problem for health care providers. Because of the high prevalence of injection drug use among HIV-positive patients admitted to hospital in Vancouver, we explored the factors associated with leaving hospital against medical advice in this population.

Methods: We reviewed records for all HIV/AIDS patients admitted to St.

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