Trajectory modelling techniques have been developed to determine subgroups within a given population and are increasingly used to better understand intra- and inter-individual variability in health outcome patterns over time. The objectives of this narrative review are to explore various trajectory modelling approaches useful to epidemiological research and give an overview of their applications and differences. Guidance for reporting on the results of trajectory modelling is also covered. Trajectory modelling techniques reviewed include latent class modelling approaches, ie, growth mixture modelling (GMM), group-based trajectory modelling (GBTM), latent class analysis (LCA), and latent transition analysis (LTA). A parallel is drawn to other individual-centered statistical approaches such as cluster analysis (CA) and sequence analysis (SA). Depending on the research question and type of data, a number of approaches can be used for trajectory modelling of health outcomes measured in longitudinal studies. However, the various terms to designate latent class modelling approaches (GMM, GBTM, LTA, LCA) are used inconsistently and often interchangeably in the available scientific literature. Improved consistency in the terminology and reporting guidelines have the potential to increase researchers’ efficiency when it comes to choosing the most appropriate technique that best suits their research questions.

There is increasing global awareness and interest in the use of cannabis for therapeutic purposes (CTP). It is clear that health care professionals need to be involved in these decisions, but often lack the education needed to engage in informed discussions with patients. This study was conducted to determine the educational needs of Canadian physicians regarding CTP. A national needs assessment survey was developed based on previous survey tools. The survey was approved by the Research Ethics Board of the McGill University Health Centre Research Institute and was provided online using LimeSurvey®. Several national physician organizations and medical education organizations informed their members of the survey. The target audience was Canadian physicians. We sought to identify and rank using 5-point Likert scales the most common factors involved in decision making about using CTP in the following categories: knowledge, experience, attitudes, and barriers. Preferred educational approaches and physician demographics were collected. Gap analysis was conducted to determine the magnitude and importance of differences between perceived and desired knowledge on all decision factors. Four hundred and twenty six responses were received, and physician responses were distributed across Canada consistent with national physician distribution. The most desired knowledge concerned “potential risks of using CTP” and “safety, warning signs and precautions for patients using CTP”. The largest gap between perceived current and desired knowledge levels was “dosing” and “the development of treatment plans”. We have identified several key educational needs among Canadian physicians regarding CTP. These data can be used to develop resources and educational programs to support clinicians in this area, as well as to guide further research to inform these gaps.

This study aimed at describing pain-related health care resource use, direct costs, and productivity loss among patients suffering from fibromyalgia syndrome (FMS). A cost-of-illness study with a sample of 57 adults having a diagnosis of FMS was conducted in the province of Quebec (Canada). Data regarding FMS-related direct costs and productivity loss from paid and unpaid work over a three-month period were collected using a standardized structured telephone interview protocol. Direct costs were valued in 2009 Canadian dollars using a societal perspective. Results showed that average direct costs over a three-month period added up to $951 per patient (SD: $710), which could be translated in a mean annual cost of $3804. The purchase of prescribed medications led to the highest costs (mean: $329, SD: $321), followed by consultations to health care professionals other than physicians (mean: $129, SD: $222) and physicians consultations (mean: $98, SD: $116). Results further showed a high economic burden for patients themselves, aside from costs covered by public or private insurers. Among the subsample of participants who had a paid job (45.6 %), an average of 5.6 days (SD: 13.2) were lost due to pain during the past three months. Among those who were not employed (54.4 %), an average of 25.1 days in household productivity (SD: 24.8) were lost. FMS is associated with a substantial socioeconomic burden. Further research is clearly needed to improve the management of this type of disorder and make better decisions regarding resource allocation.

Introduction: Multimodal treatment is recognized as the optimal paradigm for the management of chronic pain (CP). Careful balance between pharmacological and physical/psychological approaches is thus desirable but can be easily disrupted. Objectives: This study aimed at exploring the impact of the COVID-19 pandemic on pharmacological and physical/psychological treatments of CP. Methods: A Pan-Canadian cross-sectional web-based study was conducted between April 16th and May 31st 2020 among adults living with CP when the country was in the ascending slope of the first COVID-19 pandemic wave. Results: A total of 2864 participants shared their treatment experience (mean age: 49.7 years and women: 83.5%). Among medication users (n = 2533), 38.3% reported changes in their pharmacological pain treatment. The main reasons were as follows: (1) changes in pain symptoms, (2) lack of access to prescribers/cancellation of medical appointments, and (3) increased medication intake in compensation for stopping physical/psychological treatments because of the pandemic. Among participants who used physical/psychological pain management approaches before the pandemic (n = 2467), 68.3% had to modify their treatments or self-management strategies. Common reasons were lack of access to clinics/exercise facilities and the need to compensate for having to stop another type of physical/psychological treatment because of the pandemic-related public health safety measures. Conclusions: Our study underlines the negative impact of the COVID-19 pandemic on access to pain relief, which is considered a fundamental human right. Results will help to justify resource allocation and inform the development of interventions to be better prepared for waves to come and future health crises.

The Quebec Pain Registry (QPR) is a large research database of patients suffering from various chronic pain (CP) syndromes who were referred to one of five tertiary care centres in the province of Quebec (Canada). Patients were monitored using common demographics, identical clinical descriptors, and uniform validated outcomes. This paper describes the development, implementation, and research potential of the QPR. Between 2008 and 2013, 6902 patients were enrolled in the QPR, and data were collected prior to their first visit at the pain clinic and six months later. More than 90% of them (mean age ± SD: 52.76 ± 4.60, females: 59.1%) consented that their QPR data be used for research purposes. The results suggest that, compared to patients with serious chronic medical disorders, CP patients referred to tertiary care clinics are more severely impaired in multiple domains including emotional and physical functioning. The QPR is also a powerful and comprehensive tool for conducting research in a “real-world” context with 27 observational studies and satellite research projects which have been completed or are underway. It contains data on the clinical evolution of thousands of patients and provides the opportunity of answering important research questions on various aspects of CP (or specific pain syndromes) and its management.

Background: To better standardize clinical and epidemiological studies about the prevalence, risk factors, prognosis, impact and treatment of chronic low back pain, a minimum data set was developed by the National Institutes of Health (NIH) Task Force on Research Standards for Chronic Low Back Pain. The aim of the present study was to develop a culturally adapted questionnaire that could be used for chronic low back pain research among French-speaking populations in Canada. Methods: The adaptation of the French Canadian version of the minimum data set was achieved according to guidelines for the cross-cultural adaptation of self-reported measures (double forward-backward translation, expert committee, pretest among 35 patients with pain in the low back region). Minor cultural adaptations were also incorporated into the English version by the expert committee (e.g., items about race/ethnicity, education level). Results: This cross-cultural adaptation provides an equivalent French-Canadian version of the minimal data set questionnaire and a culturally adapted English-Canadian version. Modifications made to the original NIH minimum data set were minimized to facilitate comparison between the Canadian and American versions. Interpretation: The present study is a first step toward the use of a culturally adapted instrument for phenotyping French- and English-speaking low back pain patients in Canada. Clinicians and researchers will recognize the importance of this standardized tool and are encouraged to incorporate it into future research studies on chronic low back pain.