External validity in randomised controlled trials of acupuncture for osteoarthritis knee pain.
OBJECTIVES
To assess two aspects of the external validity of acupuncture research for osteoarthritis knee pain and determine the common acupoints and treatment parameters used.


METHODS
The external validity of 16 randomised controlled trials (RCTs) was investigated using a scale consisting of two aspects: reporting and performance. The reporting aspect included acupuncturist's background, study location, treatment detailed, patient characteristics, positive trial results, adverse effects and between-group statistical differences, whereas treatment appropriateness, appropriate controls and outcomes were classified as the performance aspect. Acupuncture treatment in RCTs was compared with common practice according to the literature sources and survey of acupuncturists working in different parts of Thailand.


RESULTS
The levels of external validity for the reporting and performance aspects were in the range of 31.3% to 100%. Statistic values such as mean difference and confidence interval were reported by the minority of trials (43.8%). Patient satisfaction and quality of life were seldom used (31.3%). There were minor differences between research and practice in terms of the points used (25.0%), number of treatment sessions (6.3%) and frequency (12.5%). The most frequently used points were ST34, ST35, ST36, SP6, SP9, SP10, GB34, Xiyan and ah shi points, and the commonly used treatment parameters were 20 minutes, 10-15 sessions and two treatments weekly.


CONCLUSIONS
Reporting of the external validity of acupuncture RCTs for knee pain was notably inadequate in terms of trial setting, treatment provider and statistical reporting. The majority of studies involved appropriate controls and outcomes and applied acupuncture treatments in line with practice.