Diagnostic Delays and Survival for Medicare Patients with Chronic Myeloid Leukemia in the Pre-Imatinib Era.

Timeliness of diagnosis is a quality of care measure endorsed by the Institute of Medicine. Clinical outcomes for patients with chronic myelogenous leukemia (CML) are better when tyrosine kinase inhibitors, such as imatinib, are initiated in the early stages of disease. However, the patterns of care surrounding the CML diagnosis period, as well as the relationship between diagnosis delay and overall survival in the pre-imatinib era, are unknown.

The Surveillance, Epidemiology and End Results (SEER)-Medicare linked database was used to identify traditional Medicare enrollees diagnosed with CML during 1991 through May 2001 (prior to the FDA approval of imatinib). Both inpatient and outpatient claims were analyzed from one year before, through six months following, the SEER diagnosis date. Signs, symptoms, and diagnostic studies commonly encountered in CML diagnoses were identified by CPT procedure and ICD-9 diagnosis and procedure codes. We calculated the time between the first visit for a sign or symptom and the SEER diagnosis date, and defined this time period as ‘diagnostic delay’ if it met or exceeded the median number of days for the sample. An accelerated failure time model examined variables associated with diagnostic delay. Overall survival was examined using a Cox proportional hazards model. Analyses were adjusted to account for a possible lag time in SEER cancer diagnosis dates, as well as year of diagnosis.

We studied 768 patients who met eligibility criteria. The most frequent signs and symptoms prior to CML diagnosis were infection (29.4%), anemia (22.4%), leukocytosis (13.4%) and fatigue (11.9%). The median time between any sign or symptom and CML diagnosis date in SEER was 90 days (interquartile range = 270). The median survival time was 3.5 years. The time between sign or symptom and CML diagnosis was increased for patients with at least one comorbidity (β=0.83, p < .001), and for those diagnosed at age 75 or greater (β=0.30, p < .05). Males had shortened times to diagnosis (β=-0.41, p < .01). Diagnostic delay was not a significant predictor of overall survival (HR = 1.04, 95% CI = 0.88-1.23).

The most common signs and symptoms older patients experience prior to CML diagnosis are nonspecific, which may impair diagnostic efforts. Prior to the approval and general availability of imatinib, differences in timeliness of diagnosis were observed by age, gender, and presence of comorbidities. Examination of patient-provider interactions stratified by these variables may aid efforts to standardize the diagnostic process, although diagnostic delay was not significantly associated with overall survival in the pre-imatinib era.

No relevant conflicts of interest to declare.