Prevalence of pain in Parkinson's disease: a systematic review using the modified QUADAS tool.

Pain has been studied more intensely as a symptom of Parkinson's disease (PD) in recent years. However, studies on the characteristics and prevalence of pain in PD have yielded conflicting results, prompting us to do a systematic review of the literature. A systematic review of the literature was conducted, using different databases. The last inclusion date was March 15, 2011. The modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool was used, which is especially designed for judging prevalence studies on their methodological quality. Only articles that met the predefined criteria were used in this review. We found 18 articles, of which only 8 met the methodological criteria. Prevalence frequency ranges from 40% to 85% with a mean of 67.6%. Pain is most frequently located in the lower limbs, with almost one-half of all PD patients complaining about musculoskeletal pain (46.4%). The pain fluctuates with on-off periods. Surprisingly, only 52.4% of PD patients with pain used analgesics, most often nonopioids. PD patients seem to be predisposed to develop pain and physicians should be aware of pain as a common feature of PD. As many as one-half of PD patients with pain may be missing out on a potentially useful treatment, and proper treatment could increase quality of life in PD patients.