Neglected external validity in reports of randomized trials: The example of hip and knee osteoarthritis

Objective To evaluate data reporting related to external validity from randomized controlled trials (RCTs) assessing pharmacologic and nonpharmacologic treatment for hip and knee osteoarthritis (OA). Methods All RCTs assessing pharmacologic treatments and nonpharmacologic treatments for hip and knee OA indexed between January 2002 and December 2006 were selected. A sample of 120 articles were randomly selected: 30 each assessing pharmacologic treatments, surgery or technical interventions, rehabilitation, and nonimplantable devices. Results The country was clearly reported in 25 (21%) reports, the setting described in 40 (33%) reports, and the number of centers in 54 (45%). Details about the centers (volume of care) were given in 24 (20%) reports. Rates were lower for surgical trials for the country (3%), the setting (3%), the number of centers (13%), and details about the centers (7%). The intervention was adequately described in all pharmacologic reports and in >80% of rehabilitation reports. The technical procedure was given in all surgical intervention trial reports, but the type of anesthesia was reported in 4 (13%), preoperative care in 2 (7%), and postoperative care in 15 (50%). The device was described in 93% of device trial reports, but the manufacturer was reported in only 33%. Conclusion There is low reporting of data related to external validity in reports of RCTs assessing pharmacologic and nonpharmacologic treatments for hip and knee OA.