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normal physiologic patterns and using a combination of
human insulin and insulin analogues.5
In addition to evidence showing the ineffectiveness of
SSI in controlling blood glucose concentrations, there are
several problems associated with this regimen. The regimen typically results in an increase in the number of insulin injections received, allocation of resources for frequent
medication administration, and insulin is given retrospectively for high blood glucose values and not given during
euglycemia or before anticipated hyperglycemia attributable to concurrent or planned meals.6-10 Patients are often
awakened during the night for blood glucose monitoring
and insulin therapy, which may increase the incidence of
nocturnal hypoglycemia. In addition, there is no standard
SSI regimen, and dosages vary widely between providers
and institutions.11,12 Furthermore, some evidence suggested that SSI regimens carry additional risk of glycemic
events instead of protecting against them as studies have
shown that not only has SSI been associated with an
increase in hyperglycemia and hypoglycemia, but they
have also been associated with an increased length of stay
(LOS) for hospitalized diabetic patients.8,10,13,14 Similar to
hyperglycemia, hypoglycemia poses significant burdens to
the health care system. Numerous studies have reported
the adverse effects of hypoglycemia and health-related
quality of life and treatment satisfaction.15-19 A cohort
study of more than 80,000 outpatients 66 years of age and
older with and without diabetes found that hypoglycemia
was associated with a 2.6-fold relative increase in mortality, a 72% increase in subsequent all-cause hospitalizations, and a 180% increase in suffering another episode of
hypoglycemia requiring hospitalization.20
However, there are limited data showing the direct correlation between the use of SSI (correctional insulin) and incidence of hypoglycemia in hospitalized elderly patients.
Therefore, the purpose of this study was to investigate the
effect of the use of basal and correctional insulin (B+C) versus the use of correctional insulin alone (C) on hypoglycemic
events in hospitalized elderly patients. We hypothesized that
all older patients hospitalized with or without diabetes who
were treated with B+C will have fewer hypoglycemic events
compared with those who were treated with C.

Methods
This was a single-center retrospective cohort study performed at a 691-bed community teaching hospital. The
study was approved by the institutional review board, and
informed consent was waived. Adult patients who were 65
years or older, prescribed any type of insulin between
April 1, 2016, and June 30, 2016, were included. Patients
were excluded if they were admitted to the ICU on arrival
to the hospital, if they had history of hypersensitivity to
insulin, or if they received insulin only for the management of hyperkalemia. Patients were divided based on the

Hospital Pharmacy 52(11)
insulin regimen prescribed, B+C or C. The primary outcome of the study was the comparative incidence of hypoglycemic events between groups. Secondary outcomes
were the comparative severity of hypoglycemia, which
was defined as the average blood glucose readings during
the hypoglycemic events, (1) between B+C and C groups
and (2) between patients who were 65 to 79 years and
patients who were 80 years and older. Other secondary
outcomes included LOS, hospital mortality, and need for
transfer to an ICU within 24 hours of experiencing a hypoglycemic incidence.
In this study, hypoglycemia was defined as a blood glucose level of less than 70 mg/dL as stated in our institutional
hypoglycemic protocol as well as the definition used by the
ADA.2 Basal insulin was defined as the insulin needed to
maintain good glucose control without taking into account
eating any food. Correctional insulin, also called SSI, was
defined as the dose of insulin given based on obtained capillary blood glucose measurements. The regimen consists of
short-acting insulin given 4 to 6 times per day, or prior to
meals and at bedtime.
Comparisons between the B+C group and the C group
were performed using the chi-square test for categorical variables and the Student t test for continuous variables. A P
value less than or equal to .05 was considered statistically
significant.

Results
A total of 940 patients were identified as having orders for
insulin during the study period and 231 patients were
excluded. The majority of the patients who were excluded
were admitted to the ICU on arrival to the hospital, while
others were excluded due to insulin received for hyperkalemia management or basal insulin alone was prescribed.
Seven hundred nine patients were included in primary analysis, with 144 prescribed B+C and 565 prescribed C. The
patient demographics and baseline clinical characteristics are
shown in Table 1. There were more patients with type II diabetes mellitus in the B+C group and more patients without
diabetes in group C.
More patients in the B+C group experienced an incidence
of hypoglycemia compared with those who were in the C
group (20.1% vs 12.6%, P = .012). There was also a statically significant difference in the average low blood glucose
reading in comparison between the B+C vs the C groups (50
mg/dL vs 52.5 mg/dL, P = .00075). Patients in the B+C
group experienced greater glucose variability than the
patients in the C group (Figure 1).
There was no statistically significant difference in the
average hypoglycemic readings between patients who were
younger versus patients 80 years old and older (52 mg/dL vs
51.5 mg/dL, P = .683). The hospital LOS was also similar
between group B+C and group C (7.7 days vs 7 days,
P = .074). No mortality resulted from hypoglycemic events

Table of Contents for the Digital Edition of Hospital Pharmacy - December 2017