Our findings in this study confirm those in our earlier reports that CSII therapy can be maintained in most insulin pump patients during a hospitalization.16,17
A smaller group of these patients had to be transitioned off CSII therapy and placed on alternative insulin regimens because they did not meet the criteria for continued CSII use as set forth by our hospital policy guidelines. Aside from the one instance of transient hyperglycemia due to a catheter kinking, no adverse events occurred among those patients who remained on CSII. The only other study examining the topic of inpatient CSII use also noted no significant safety issues.12
In the current study, a third category of inpatient CSII users was identified, one in which insulin pumps were used intermittently. Others have recognized that patients may not be on insulin pumps for the entire length of their hospital stay.12
This intermittent use of insulin pumps in the hospital probably reflected a dynamic interplay between the desire of patients to continue using their technology whenever possible and their changing clinical status, which would require constant reevaluation of the appropriateness of the therapy. The findings of three categories of CSII users underscores the diversity of these patients in the hospital and further supports the need for the type of institutional standards described here.
This article reflects an assessment of the largest number of hospitalizations involving insulin pump users, with the number of unique patients encountered nearly doubling since our last report and the number of hospitalizations being evaluated increasing more than two-fold.16,17
It is not clear why the number of cases with CSII encountered in our hospital has been increasing. This rise likely is not due simply to a general increase in the number of diabetes hospitalizations. The proportion of diabetes-associated hospitalizations in our institution was 18% in 2006, 22% in 2007, and 19% in both 2008 and 2009. Thus, when our greatest number of diabetes hospitalizations occurred, the number of CSII admissions was least (in 2007). Moreover, the number of hospitalizations involving insulin pump patients increased in 2008 and 2009 despite the percentage of overall inpatient diabetes cases remaining flat in these years.
One explanation of why we have witnessed more patients admitted with insulin pumps is that use of CSII itself may be increasing. Testing this hypothesis would require some knowledge of the regional insulin pump outpatient population, but such data do not exist in the form of a disease management registry in the public domain. As we are a regional referral center, another possibility for the rise in insulin pump patient cases may be that the most seriously ill CSII patients are presenting to our institution. It would be of interest to know if other hospitals are observing similar increases in the number of insulin pump patients. Ongoing surveillance will establish whether the increasing trend continues.
The result of this analysis is greater insight into the characteristics of the insulin pump patients we encounter in the hospital. One-third of the patients accounted for nearly two-thirds of the hospitalizations, which may imply a high degree of chronic illness in some insulin pump users. Overall, patients had a long duration of diabetes, and on average, they had been on CSII therapy for several years. Hence they were likely to be familiar both with management of their diabetes and with insulin pump technology.
In general, institutional compliance with insulin pump procedures was high. Adherence remained high over time and even improved for some measures. It cannot be ascertained from a retrospective analysis why some measures improved, but possibilities include improved familiarity with inpatient insulin pump processes as more cases were encountered or the result of ongoing staff educational efforts on the topic. Underperformance with the bedside flow sheet was a consistent shortfall. We were not able to determine whether these were missing because of not being completed or simply because the documents had not been scanned into the electronic medical record. The bedside flow sheet is a key method by which the patient communicates pump data (e.g., basal insulin rates and bolus amounts and glucose data) to the hospital staff that should be documented in the medical record. An examination of the chain of custody of the bedside flow sheet needs to occur, from the patient bedside to the scanning process.
This updated analysis does continue to raise a question as to whether CSII therapy is more advantageous than other insulin regimens for controlling inpatient hyperglycemia. The average glucose during “pump on” hospitalizations and the prevalence of hyperglycemia in these patients was similar to those values in the “pump off” and “intermittent pump” groups. Mean bedside glucose levels, the prevalence of hypoglycemia and hyperglycemia, and the frequencies of hypoglycemic and hyperglycemic measurements in this analysis were consistent with what we have reported previously.17
Moreover, hyperglycemia and hypoglycemia among these CSII patients continues to be more frequent than what we have historically reported for our general diabetes inpatient population.20
We had earlier thought that maintaining CSII in the hospital offered an advantage regarding less hypo-glycemia, but our findings from this larger data set did not confirm this expectation.16
Since CSII patients potentially face the same stressors in the hospital as those affecting any other diabetes patient, insulin pumps may not offer superior glycemic control compared with other insulin treatment strategies. Additionally, the short length of stay in many cases would not allow sufficient time to optimize pump settings and monitor effects.
There are some limitations to our analysis. The sample sizes, particularly in the “pump off” and “intermittent pump” categories, are very small, and definite conclusions about differences in glucose control among the three inpatient scenarios cannot be made. Although this review examines the largest number of hospitalizations involving insulin pump patients reported to date, it still took four years to accrue just 125 cases for analysis. This low volume of encounters probably will not allow hospital staff to become proficient with insulin pump technology and reinforces the need for a standardized approach that practitioners can implement with such patients when hospital admission is required.
Another limitation is that we cannot be certain that we identified every hospitalized patient who was receiving insulin pump therapy. The data indicate that not every patient received an endocrinology consultation, so the endocrinology consultants may not have been aware of some cases until toward the end of the hospital stay or even after discharge. Patients on insulin pumps are co-mingled with the general diabetes patient population from a coding perspective, i.e., they do not receive a unique diagnostic code that can distinguish them from other diabetes patients in an electronic database. Due to the lack of a specific identifier for insulin pump patients, it will be difficult to conduct large scale analyses of hospitalizations involving pump users unless institutions develop registries like ours. Applying existing ICD-9 codes to CSII users would allow for easier identification in electronic data for future retrospective analysis. Our process of identifying patients on insulin pumps still requires an endocrinology consultation request from the admitting team, which makes it all the more necessary to continue educating inpatient staff about this policy so that all pump patients can be seen and the outcomes tracked.
A third limitation is that we have not yet addressed patient satisfaction with our policy and procedures. A study did report data on the topic of patient satisfaction with regard to inpatient insulin pump therapy, which is something we need to begin evaluating.12
Additionally, we should evaluate staff satisfaction with our approach to these patients.
Beyond the challenges and limitations noted here is how best to provide ongoing education to inpatient staff regarding insulin pump procedures. Staff turnover occurs constantly. We have been providing ongoing briefings to the nursing staff about the insulin pump policy, and resident physicians have access to online modules on inpatient diabetes that include information about our inpatient CSII procedures,22
but we need to develop a more comprehensive approach that includes all inpatient providers.
Despite these limitations and challenges, this analysis provided us the most detail yet about characteristics of the inpatient population using insulin pumps. A policy on inpatient CSII use can be successfully implemented, and patients on outpatient treatment can have therapy safely transitioned to the hospital. High compliance with required process measures can be achieved, although there continues to be room to improve in some areas. Hospital glycemic control among CSII users was no worse than that achieved when alternative insulin regimens were required. Further study is needed to determine how best to optimize glycemic control when CSII therapy is used in the hospital, to improve case identification, and to provide continuing education on the processes needed to care for these patients.