Comprehensive Examination of Therapies for Pain in Parkinson's Disease: A Systematic Review and Meta-Analysis.

Pain in Parkinson's disease (PD) is a debilitating symptom with a prevalence of 68%, yet is untreated 50% of the time. What is unclear, however, is which treatment is optimal for minimizing pain severity in PD. Thus, the objective of this systematic review and meta-analysis was to investigate the efficacy of a variety of novel, complimentary, and conventional treatments for pain in PD and elucidate which therapy is the most effective. A systematic search was performed using MEDLINE, PsycINFO, Embase, CINAHL, and CENTRAL databases. To identify additional articles, manual searches of reference lists of included trials were also searched. Major neurology conference proceedings occurring between January 2014 and February 2018 were also searched to identify unpublished studies that may be potentially eligible. Twenty-five randomized controlled trials that encompassed medical, surgical, and complementary therapies met our inclusion criteria and exhibited moderate quality evidence. Two reviewers conducted assessments for study eligibility, risk of bias, data extraction, and quality of evidence rating. A conservative random-effects model was used to pool effect estimates of pain severity. The greatest reductions in pain were found with safinamide (Standardized mean difference = -4.83, 95% CI [-5.07 to -4.59], p < 0.0001), followed by cannabinoids and opioids, multidisciplinary team care, catechol-O-methyltransferase inhibitors, and electrical and Chinese therapies. Moderate effects in reducing pain were in pardoprunox and surgery, while the weakest effects were in dopaminergic agonists and miscellaneous therapies. Safinamide is an important adjunct to standard parkinsonian medication for alleviating pain in PD.