Background: High-quality doctor-patient communication is essential for patients with serious illnesses. The reliability and validity of Consumer Assessment of Healthcare Providers and Systems (CAHPS®) communication items among these patients are unknown. Methods: Five CAHPS communication items, a 4-item Advance Care Planning (ACP) engagement scale, 5-item confidence in others' knowledge of ACP medical wishes scale, and a question about confidence in filling out ACP-related medical forms were administered to 1100 patients (20% response rate) with serious illness receiving primary care at three University of California Health Systems. Results: Average age was 69 (range 22-102); 52% male, 18% Hispanic, 9% Asian, and 7% Black; 24% had high school or less education. Eigenvalues and internal consistency reliability (0.88) supported a 5-item communication scale. Item characteristic curves showed a monotonic relationship of response options with the communication score. Item thresholds indicated that most patients reported positive patient experiences (i.e., items were negatively skewed). Item slopes ranging from 2.52 to 5.10 confirmed that all items were strongly related to the communication score. Information (reliability) of the communication scale was higher for assessing patients with negative experiences of care than for the positive end of the spectrum. Communication was positively correlated with confidence in other's knowledge of ACP medical wishes (r = 0.32, p < 0.0001), ACP engagement (r = 0.14, p < 0.0001), and confidence in filling out ACP-related medical forms (r = 0.09, p = 0.0022). Conclusions: These findings support the use of CAHPS survey items to assess communication among patients with serious illnesses in primary care. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04012749.
Keywords: CAHPS®; advance care planning; communication; survey.