Studies of pain management in osteoarthritis: bedside to policy

Abstract

Objective: Osteoarthritis (OA) is a debilitating chronic condition requiring long-term treatment of pain and functional impairment. Our objective was to characterize studies addressing management of OA-related pain with respect to the breadth of interventions, trial duration and size, outcome measures, and funding sources.

Design: We identified studies focused on 'pain' and 'osteoarthritis' from ClinicalTrals.gov and abstracted data on study status, sample size, design, funding source, duration, outcomes measured, and interventions evaluated. We examined associations among intervention type, funding source, sample size, duration, and outcomes measured.

Results: We identified 287 registered studies, of which 69% investigated pharmacologic interventions, 11% behavioral interventions, and 5% surgical procedures or devices, while the remainder examined other types of interventions. Eighty-seven percent evaluated knee OA. The average sample size was 290 subjects and average study duration was 7.4 months, with 52% using durations ≤3 months and 21% ≥12 months. Industry funded 64% of studies, either fully or partially. Of 180 completed studies, 139 were pharmacologic studies. Of these, 34 (24%) posted results to the registry. Among the studies funded by industry, 60% had durations ≤3 months as compared with 36% among non-industry funded studies (P < 0.0001). Behavioral intervention trials tended to be of longer duration than pharmacologic trials and were less likely to be funded by industry.

Conclusion: Over half of OA pain studies and >80% of those funded by industry used trial durations of less than 6 months. Future studies should take into consideration the need for long-term pain management for OA when designing trial protocols.

Keywords: Clinical trials; Osteoarthritis; Pain; Registry.

Figure 1. Collection and Exclusion of Clinical Trials

This figure depicts the process by which trials were collected from ClinicalTrials.gov. The initial search results were examined and studies that did not focus on treatments for OA pain were excluded. The included trials are further separated by the type of intervention they evaluate: pharmacologic, behavioral, surgical, or other.

Figure 2. Average Study Duration by Type of Intervention Investigated

This figure shows average clinical trial study duration, stratified by intervention type (behavioral, pharmacologic, surgical procedures and devices, or other). Average duration is reported in months. The 95% confidence intervals are indicated in the graph.