The cohort consisted of 176,231 participants (Fig. 1); we excluded those erroneously identified including 21 who were < 49 years, 16 who had a history of colorectal cancer, 924 participants who were not members at the index date, and 48 who died before the index date. Overall, 53% of the cohort were female; the median age was 59, with 34% aged 49–55, 22% aged 56–59, 18% aged 64, 12% aged 65–70, and 14% aged 71 or older (Table 1); 11% were Asian, 21% Hispanic/Latino, 7% black, 51% White, 3% other/mixed race, and 7% unknown. Over the course of the study period, approximately 4% terminated KP membership (N = 6295) and < 1% died (N = 669).
Approximately 10% (N = 16,918) used the oPAP button to request a FIT kit. In bivariate comparisons, we found significant differences between the button and non-button groups on both demographics and proxy measures of engagement. A significantly higher proportion of the button group were white race (62% in the button group vs. 50% non-button), and were over the age of 71 (22% vs. 13%); a significantly smaller proportion of the button group were aged 49–55 (27% vs. 35%), were Asian (9% vs. 11%) or Hispanic (15% vs. 22%), or required an interpreter (2% vs. 4%). For proxy measures of engagement, the button group had a significantly higher proportion of ≥ 20 patient portal logins in the past year (33% vs. 12%) as well as a significantly higher proportion of frequent outpatient utilization, defined as 20 or more outpatient visits in the past year (34% vs. 23%). Those in the button group had a significantly higher proportion of those with a CCI score of 2 or 3 (14% vs. 10%) and ≥ 4 (6% vs. 4%).
Among those in the button group, 83% completed a FIT kit, compared to 37% of the non-button group (Fig. 2). Using the inverse probability of treatment weights to balance the groups on demographic and proxy engagement characteristics (see weighted characteristics in Table 2), we found that those who used the FIT kit button had 3.8 times the odds of completing a FIT kit in comparison to participants who logged into the patient portal during the study period but did not use the button (odds ratio (OR), 3.77; 95% confidence interval (CI), 3.57–3.98) adjusting for gender, race/ethnicity, age, interpreter needs, recently utilized medical center, prior patient portal logins, prior missed appointments, prior total utilization, and weighted CCI (Fig. 3). In the non-button group, those who did not login to the patient portal during the study period had 75% less odds of completing a FIT kit compared to those who logged in but not use the FIT kit button.
To estimate the impact of the button for patients who had not completed CRC screening in the past, we examined past FIT kit use in the button group. We determined that 12,081 (71%) of the button-user group were KPSC members and eligible for a FIT kit in the year prior to the release of the button (Table 3). Of those, 63% (7593) completed a FIT kit prior to the availability of the button compared to 87% (10,469) in the year after the button became available (McNemar’s test p < 0.0001), an increase of 2876 patients.
The mean number of days to FIT kit completion was 56 days in the button group compared to 90 days in the non-button group (p < 0.001). Overall, 4% of the both groups who completed a FIT kit required additional CRC screening for positive or inconclusive results. For those patients who had a positive FIT result requiring additional screening, 8% of the button group did not have subsequent recommended screening vs. 18% in the non-button group.
We also examined CRC diagnosis: 19 patients (≤ 1%) in the button group were diagnosed with a new primary CRC during the study period: 37% stage I, 21% stage 2, 32% stage III, and 11% stage IV. Among the non-button group, 133 (≤ 1%) had a new primary CRC diagnosed during the study period: 20% stage I, 18% stage 2, 39% stage III, 17% stage IV, and 5% unstaged.