Background: The increasing incidence in multiple myeloma (MM), coupled with improved efficacy of therapies, warrant population-based studies of diagnosis delay which could lead to disease-related complications.
Methods: We analyzed tumor registry data and provider claims in the SEER-Medicare database, a geographically and racially diverse sample of Medicare enrollees with confirmed MM. Using extant selection criteria to study eligible MM patients, we identified claims with anemia (An) or back pain (BP) codes, conditions related to MM. We estimated the period of time between first claim for An or BP and confirmed MM diagnosis. We defined delay as ≥98 days (the median) between initial An or BP claim and MM diagnosis, and estimated logit models to predict sociodemographic and clinical factors associated with delay. We also estimated logit models to predict the likelihood of renal or skeletal complications following MM diagnosis. The study period was one year before, through six months following, diagnosis. Analyses were adjusted for a known 30-day lag time in MM diagnosis dates in SEER.
Results: From the analytic sample of 5,185 patients, 3,600 had a diagnosis for An (2,576) and/or BP (2,012) prior to MM diagnosis. Male gender (OR 0.73, 95% CI 0.64–0.84) and northeast region (0.79, 0.65–0.96) decreased the likelihood of delay. Over 60% of patients had ≥ 1 Charlson comorbidity; higher Charlson scores and the presence of both An and BP increased likelihood of delay, but were strongly correlated, and an interaction term with these variables in the model was significant. Of the 5,112 patients with no history of renal or skeletal complications, 1,742 (34%) experienced a complication within six months after MM diagnosis. After adjustment for gender, age, race, and subsequent chemotherapy use, patients with: higher Charlson scores (1.17, 1.03–1.33); initial diagnosis during an inpatient stay (2.40, 1.92–3.00), and; no UPEP, SPEP, or bone marrow biopsy as part of the MM workup (1.68, 1.48–1.92) were more likely to experience a complication (29% of patients had neither PEP nor biopsies recorded). Delay between An or BP diagnosis and MM was not associated with likelihood of complication (0.96, 0.91–1.01).
Conclusions: Despite the presence of two classic signs and symptoms of MM, gender and geography significantly influence diagnosis delays. The surprising finding that both anemia and back pain delay diagnosis is partly explained by increased comorbidity in these patients. These findings highlight the importance of considering MM as part of the routine workup for anemia in elderly patients. The existence of comorbidity in these patients may obscure the clinical presentation, resulting in delayed diagnosis. Underuse of common tests to diagnose myeloma may result in poor outcomes, and could be a focus of quality improvement efforts.
Disclosure: No relevant conflicts of interest to declare.