Complex Regional Pain Syndrome After Distal Radius Fracture Is Uncommon and Is Often Associated With Fibromyalgia.

BACKGROUND: Complex regional pain syndrome (CRPS) is frequently diagnosed in patients recovering from surgery or injury. The symptoms and signs included in consensus diagnostic criteria for CRPS are expected after injury. Categorizing symptoms and signs that occur on a continuum as disproportionate or not is subjective and prone to bias. Psychiatrists and psychologists do not diagnose CRPS and instead measure and treat anxiety and catastrophic thinking on its continuum. Given the expected variation in subjective diagnoses such as CRPS, this study addresses factors associated with use of this diagnosis and how it influences care.

QUESTIONS/PURPOSES: (1) Among patients recovering from fracture of the distal radius, what factors are associated with the diagnosis of CRPS? (2) Are patients diagnosed with CRPS after distal radius fractures, as opposed to those without CRPS, more likely to have a bone scan, stellate ganglion block, therapy, or subsequent surgery?

METHODS: Using the Truven database, we identified 59,765 patients treated for a distal radius fracture from 2012 to 2014, of whom 114 (0.19%) were diagnosed with CRPS. The Truven Health MarketScan database is an administrative claims data set of commercially insured patients and this analysis only included patients with complete enrollment from 2012 through 2014. Bivariate analyses sought differences between patients diagnosed with and patients not diagnosed with CRPS. All factors with p < 0.05 were included in a multivariable logistic regression model.

RESULTS: The covariates older age (odds ratio [OR], 1.029; 95% confidence interval [CI], 1.011-1.048; p = 0.002), gender (women at greater risk, OR, 3.86; CI, 1.99-7.49; p < 0.001), concomitant fracture of the distal ulna (OR, 1.54; CI, 1.05-2.23; p = 0.029), open fracture (OR, 0.414; CI, 0.192-0.895; p = 0.025), and comorbid fibromyalgia (OR, 16.0; CI, 4.92-51.8; p < 0.001) were independently associated with a diagnosis of CRPS among patients recovering from a fracture of the distal radius. Patients diagnosed with CRPS are more likely than other patients with a distal radius fracture to have had a bone scan (OR, 66.0; CI, 8.19-532; p < 0.001), physical or occupational therapy (OR, 3.89; CI, 2.68-5.67; p < 0.001), and subsequent wrist surgery (OR, 2.52; CI, 1.65-3.84; p < 0.001). No one had a stellate ganglion injection.

CONCLUSIONS: We found that a coded diagnosis of CPRS is uncommonly applied to patients on the higher range of pain, stiffness, and limitations after fracture of the distal radius-most commonly in women and in association with another nonspecific, objectively unverifiable diagnosis (fibromyalgia)-and that this label may lead to more testing and invasive treatment. Future research should address the utility and value of diagnoses that create subjective categories for aspects of human illness that occur on a continuum.

LEVEL OF EVIDENCE: Level III, prognostic study.