We found that many veterans 70 years or older are not receiving any follow-up after incomplete or positive screening FOBT results. In addition, while 64% of elderly veterans with positive FOBT results received some type of follow-up within 1 year, only 42% received complete colon evaluation. The cumulative incidence of complete colon evaluation after a positive result was low regardless of age or comorbidity. Instead, other factors, such as VA site, number of positive FOBT cards, and number of VA outpatient visits were predictive of receiving complete colon evaluation, although the incidence never exceeded 60%. Also, chart documentation indicated patients who should not have been screened in the first place accounted for 38% of older patients who did not receive complete colon evaluation within 1 year, and most (>75%) patients who did not receive complete colon evaluation in the first year never did receive complete follow-up even during the next 5 years.
Low rates of follow-up after a positive screening FOBT result are found in many health care systems, with the majority of studies showing less than 60% of older patients receive complete colon evaluation within 1 year.9–13, 15–17, 19, 28
Despite this widespread problem, previous studies have not determined the extent to which lack of follow-up is due to screening patients whose age, comorbidity, or preferences would not permit complete colon evaluation. Findings from previous studies have been mixed regarding the effect of age and comorbidity on receipt of complete colon evaluation after positive FOBT results and they have been limited by narrow geographic area or included FOBT performed for non-screening purposes, and prior VA studies have not included follow-up outside the VA.10–13, 15–20, 29
Novel aspects of our study are that we used a geographically diverse screened population and its spectrum of FOBT results (e.g., number of positive cards, incomplete tests) and identified follow-up using objective real world data, including claims data from outside the VA through Medicare, which accounted for 15% of complete colon evaluations.
While we found age and comorbidity were not associated with receipt of complete colon evaluation after positive FOBT results, 38% of patients without complete follow-up had chart documentation that they refused or had long-standing health problems which did not permit follow-up. We also found that among patients without complete follow-up within 1 year, less than 25% received complete follow-up even over the subsequent 5 years. This suggests screening patients in whom complete colon evaluation would never be pursued substantially contributes to lack of follow-up among older patients. This may be explained in two possible ways. First, a discussion about the need to follow-up a positive result with colonoscopy may not happen at the time of screening. Prior studies have shown clinicians often fail to discuss key information about colorectal cancer screening with patients, especially risks of follow-up procedures.30, 31
Second, previous studies have shown that FOBT screening is poorly targeted to healthy older patients for many reasons, including quality indicators which often promote screening regardless of comorbidity or preferences.7, 32
Failure to complete follow-up in older patients for whom age, comorbidity or preferences were not documented as contraindications to follow-up was also common (62%). In fact, 43% of patients who did not receive complete colon evaluation lacked acknowledgment of the positive FOBT result in progress notes, suggesting clinicians may not have known about these results. In addition, clinicians were less likely to complete follow-up if only one FOBT card was positive or if a patient reported not following dietary instructions. However, guidelines recommend complete colon evaluation if any FOBT card is positive.4,5
Similarly, dietary indiscretion is not a reason to avoid follow-up.33
Also, access to timely colonoscopy may be difficult at some VA facilities if the number of gastroenterologists is low or the rate of positive FOBT is especially high, such as Site B, which used a more sensitive FOBT than the other facilities. Conversely, some facilities, such as Sites A and C, had electronic data systems that informed clinicians of screening results and tracked endoscopy procedures, which increase follow-up. 34, 35
While increasing use of electronic reminder and notification systems for positive FOBT results have led to some increases in the percentage of patients undergoing complete colon evaluation in both the VA and integrated health systems,19, 34, 35
these likely encourage follow-up in all patients indiscriminately despite substantial differences in potential benefits and risks. Our findings that a substantial number of older patients should not have been screened in the first place suggest that interventions mandating follow-up may have the unintended consequence of worsening quality of care in these patients. In addition, the number of positive FOBT cards, VA facility, and number of visits should not be the major predictors of follow-up. Rather, quality improvement initiatives should encourage clinicians to weigh risks and benefits at each step in the screening process, in the context of a patient’s age, comorbidity, and preferences.36
Our study has several limitations. Although we supplemented two national claims databases with chart review, we may have missed some tests performed outside the VA system, as Medicare does not capture tests paid for privately and Medicare claims are not reliably reported for patients enrolled in Medicare Managed Care so they were excluded from our study. Second, as our study predates quality improvement efforts initiated at the VA in 2005, current patterns may be different. However, a prior study found that follow-up has not been increasing over time (1991–2006),17
and even in 2007 less than a third of patients received complete colon evaluation within 60 days of a positive FOBT result, suggesting problems with follow-up persist.37
Third, while our study included over 2,400 patients screened with FOBT, only 212 had a positive result, which may have limited our power to detect small differences between predictors of follow-up. Fourth, medical records sometimes lack details about why a patient refused or did not receive follow-up. However, the medical record is the official document of the follow-up decision that was actually made. This is an advantage over using clinician self-report which may not represent real world decision-making in a busy practice setting. 38
Fifth, our cohort is primarily comprised of men who use the VA, so the generalizability of our findings to persons who do not use the VA is uncertain. Yet, understanding follow-up within the VA is important in its own right, because the VA is the largest health care system in the U.S. and a leader in improving health care quality.
In conclusion, low follow-up rates after a positive FOBT result are seen regardless of whether patients are 70–74 years without comorbidity or 80 years or older with comorbidity. These findings argue against the approach of screening indiscriminately with FOBT and then targeting follow-up based on age and comorbidity since like colorectal cancer screening, FOBT follow-up in older adults is not well targeted. Chart documentation indicates failure to complete follow-up is due to problems with screening patients in whom follow-up is not appropriate as well as failing to complete follow-up in patients who should have received follow-up. Quality improvement initiatives should encourage individualized screening decisions in older patients, and facilitate timely follow-up of positive FOBT results in patients whose comorbidity and preferences make follow-up appropriate.