Statistical Analysis
REGRESSION
Descriptive statistics were used for patient and provider characteristics, provider reaction to the ACP notification, and survey results. Results were presented in the following groups: (1) patients referred to the Meta-LARC ACP study, (2) patients who were not referred to the Meta-LARC ACP study, and (3) all patients identified by the ACP notification. Two patients were referred more than once, and each was counted as 1 referral per patient. Percentages were calculated for dichotomous and categorical data and mean and SD or median and IQR for continuous variables. We describe the frequency of occurrence of documentation related to ACP, advance directives, health care power of attorney, or POLST forms. Health care utilization (primary care visits and hospitalizations) were also described.A logistic regression was performed using deciles to identify when a significant change in number of notification and referral to study occurred. As the deciles had overlapping notification values, we categorized the notifications into 9 categories (1, 2, 3, 4, 5, 6, 7 to 8, 9 to 13, or greater than 13 notifications). It was found that at 6 notifications there was a significant change in referral response (The chi-square test was used to compare associations between notifications (5 or less notifications and greater than 5 notifications) and (1) referral to the study, (2) ACP note documentation, and (3) ACP billing. We also examined associations between referral to study and (1) ACP documentation and (2) ACP billing. Associations where the primary care provider had an active role in (eg, referral response in the notification, note documentation, and billing) were only evaluated. Therefore, we did not compare associations with advance directives, health care power of attorney, or POLST forms, as these can be placed or submitted by patients and providers outside of the primary care clinic. Lastly, baseline patient characteristics and association with referral to study were evaluated using simple logistic regression models and complete data. Reference groups for the analysis were age (<65 years old), race (White), and sex (female). We excluded ethnicity, as the majority of patients were non-Hispanic, and insurance status, as the majority of patients were Medicare. Odds ratio (OR), CI around OR, and 