Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Original study sample flow diagram. Participants may take more than one oral analgesic at each time point; effective complete-case analysis samples for each visit are lower than these frequencies. CES-D, Center for Epidemiological Studies Depression Scale; K-L grade, Kellgren–Lawrence Grade; NSAIDs, non-steroidal anti-inflammatory drugs; OAI, Osteoarthritis Initiative
