In this analysis of the first year of a patient navigator program at our institution, the total number of colonoscopies increased by 11%; this change was driven by a large increase in colonoscopies performed on Medicaid outpatients, the principal target of the navigator program. In this subgroup, the quantity of colonoscopies increased by 56%. Although the effect of patient navigation on quality indicators may be expected to be limited to preparation quality, we analyzed cecal intubation rates and adenoma detection so as to assess whether the navigator program affected quality metrics simply by virtue of the attendant increase in colonoscopy quantity. Analysis of these quality outcomes demonstrates that this increase in quantity was achieved without sacrificing quality.
Our findings regarding the efficacy of the patient navigation program are congruent with previously published studies of patient navigation. Two randomized trials, which included a total of 72 navigated patients, demonstrated that patients randomized to a patient navigator (as opposed to usual care) had greater colonoscopy completion rates and higher overall colorectal cancer screening rates. 10, 11
A larger randomized trial, in which 409 patients were randomized to navigation, resulted in successful screening rates of 27% compared to 11% of controls. 14
The results of that trial, however, may not be generalizable to our population, as only 3% of the population had Medicaid, as opposed to 87% of the navigated patients in the present study.
In an observational study of a navigator program instituted at a public hospital by Nash, et al, patient navigation was associated with a decrease in missed appointments and an increase in overall volume similar to the increase in the Medicaid outpatients in our analysis. 13
However, in that study, the institution of the navigator program and direct referral program occurred during the same period as the implementation of major capacity enhancements to the endoscopy suite, making it impossible to ascertain to what extent the navigator program itself contributed to the increase in volume. In our study, no such changes occurred during the analyzed period, and the heterogeneous nature of our patient population allowed for a functional control group in the volume analysis, i.e. the private outpatients. Among private outpatients, colonoscopy volume increased by <1%, strongly suggesting that the increase in volume among Medicaid outpatients was solely an effect of the navigator program, as opposed to a secular trend in screening rates.
Our study represents the largest published sample of patients undergoing navigator-facilitated colonoscopy to date. During a marked increase in procedure volume, as observed among outpatients with Medicaid in this analysis, maintenance of quality standards is imperative so as to maximize the public health benefit of this intervention. As such, we sought to measure quality metrics including cecal intubation rate, preparation quality, and adenoma detection rate, and compare these measures to established quality standards. The cecal intubation rate of 97% among navigated patients exceeds the benchmark of 95%, and the adenoma detection of 33% among men and 22% among women exceed the benchmark standards of 25% among men and 15% among women. 16
The prevalence of adenomas among navigated patients in this analysis exceeds that reported in previously published studies of navigator-facilitated colonoscopy, though the prevalence of carcinoma is similar. In a study by Chen, et al, in which 353 patients underwent colonoscopy with the aid of a navigator, ≥1 adenoma was found in 58 patients (16%), including 14 males (22.5%) and 44 females (15%); adenocarcinoma was present in two patients (0.6%). 9
Likewise, in the study by Nash, et al at the public hospital, the total neoplasia detection rate during the navigator period was 15%. 13
The patient demographics in these two studies with regard to the age and gender distribution are similar to those of the present study. Moreover, the prevalence of adenomas among navigated patients is higher than the adenoma prevalence measured at our institution in the time period preceding the onset of the navigator program: 29% for males and 15% for females. An explanation of the higher adenoma rate observed in our navigated cohort is elusive, and might be related to incompletely measured differences in baseline risk, including racial and ethnic makeup, in addition to possible differences in operator technique. Since this analysis was limited to the first year of the navigator program, it is possible that the patients who underwent colonoscopy represent a higher risk group that was eager to undergo screening once a new route was established; however, this does not appear to be the case based on family history or “alarm” symptoms as documented in the colonoscopy report. Monitoring the adenoma detection rates in the subsequent years of this program will reveal whether the currently-observed adenoma prevalence is representative of the target population as a whole.
With regards to preparation quality, quality guidelines indicate that this important parameter should be recorded in all colonoscopy reports. 16
In our analysis, this was recorded in 96% of patients undergoing navigator-facilitated colonoscopy, which was significantly greater than that noted in non-navigated Medicaid outpatients and private outpatients.
Our findings regarding preparation quality among patients undergoing navigator-assisted colonoscopy reveal a modest and statistically significant improvement in preparation quality compared to non-navigated Medicaid outpatients. This improvement is observed in two analyses, whether defining the undesired outcome as suboptimal (defined as fair/poor) or poor. However, the overall quality of preparation, while superior to that of non-navigated Medicaid outpatients, was far inferior to that of private patients. We have previously reported the high rates of suboptimal preparation quality among Medicaid patients in our institution, 17
and it appears that the navigator program appears to only partially alleviate this disparity, with a large difference remaining between these patients and private patients. The reasons for this disparity are unknown, but appear to be independent of age, ethnicity, indication, and time of the colonoscopy. 17
The modest improvement in preparation quality observed among navigated patients is further tempered by the fact that there was a secular trend of declining preparation quality among non-navigated Medicaid outpatients comparing the pre-navigator period to the navigator period. This is to be expected, as patients in the navigator period whose comorbid illnesses precluded navigation may be expected to have inferior preparation quality due to these very comorbidities.18
Thus, there exists the possibility that the improvement observed among navigated patients represents selection bias, in which the Medicaid outpatients who were bound to have superior bowel preparations underwent navigation; this would result in improved preparation rates in the navigated group and a decline in preparation quality in the non-navigated Medicaid outpatient group, as is observed.
In a prior study which reported the preparation qualities among patients in a navigator program, 9
the proportion of patients with inadequate preparation was 5%, similar to the 7% poor preparation rate observed among navigated patients in our study. There was no formal comparison to a control group with regard to preparation quality in the study by Chen, et al, but the authors reported that the historic inadequate preparation rate was 12%. Our results suggest that, at our institution, the preparation quality of patients undergoing navigator-facilitated colonoscopy remains inferior to that of private patients, and future efforts will focus on identifying barriers to optimal preparation in this patient population.
Our study has a number of limitations. As a single institution study, the generalizability of our findings is uncertain; the effectiveness on a patient navigation program is likely to be critically dependent on the performance of the individual navigators. However, this study, seen in the context of previously performed studies of patient navigation, 11-14
supports the notion that patient navigation can result in increased screening rates among urban minorities, while maintaining key quality measures. As the patient navigator program was instituted in conjunction with a direct endoscopy referral service, the relative contribution of these two innovations to the overall result is unknown. Information regarding neoplastic findings in this analysis was limited to those patients who underwent navigation. This was due to the labor intensive process of manually reviewing histopathologic records. However, the purpose of calculating adenoma prevalence in all navigator-facilitated colonoscopies was to assess how the adenoma detection rate compared to established quality benchmarks as well as the previously-measured overall adenoma prevalence in our institution, which was accomplished using the data collected.
Our findings regarding preparation quality are limited by the possibility of selection bias, as described above. Moreover, preparation quality was assessed by individual operators and there was no standardization of preparation quality definitions between operators. To partially mitigate this latter limitation, we repeated the analysis of preparation quality so as to include a general definition (“suboptimal”) as well as a more restrictive definition (“poor”). The protective effect of patient navigation remained, and appeared to be strengthened when using the more restrictive definition.
In conclusion, in this largest reported cohort of navigator-facilitated colonoscopy to date, the introduction of a patient navigator/direct endoscopic referral program was associated with an increase in volume of colonoscopy among outpatients with Medicaid, the principal target of the navigator program. This increase occurred despite an overall minimal secular change in volume compared to the year prior to the introduction of the program. During this increase in screening quantity, quality measures were maintained and, in the case of cecal intubation rate and adenoma detection, exceeded guideline-established quality benchmarks. Future studies should investigate the long-term effect of navigator programs on colonoscopy quantity and quality. Future studies should also identify the causes of, and devise strategies to prevent, suboptimal bowel preparation in this population.