Yousuf, Salman J. DO, MS*,†; Jones, Leslie S. MD*
*Department of Ophthalmology, Howard University Hospital, Washington, District of Columbia
†Mercy Catholic Medical Center, Mercy Health System of Southeast Pennsylvania, Philadelphia, PA
Disclosure: The authors declare no conflict of interest.
Reprints: Leslie S. Jones, MD, Department of Ophthalmology, Howard University Hospital, Washington, District of Columbia (e-mail: email@example.com).
Received May 4, 2010
Accepted July 27, 2010
Purpose: To describe the patterns and predictors of adherence to topical glaucoma medication during hospitalization for medical disease.
Design: Retrospective, nonrandomized, and comparative case-series.
Methods: Medical records of all the patients hospitalized with a secondary diagnosis of glaucoma between January 2006 and March 2009 were reviewed. Baseline characteristics of all patients were recorded including sex, ethnicity, age, primary medical diagnosis, and the length of stay. The outpatient topical glaucoma medications known on admission and prescribed at the time of admission were recorded, and the numbers of outpatient and inpatient systemic medications were tracked. Adherence was defined as receiving more than 75% of the expected doses. The patient discharge instructions were also reviewed.
Results: Of the 184 patients included, 98 (53%) were female, 102 (55%) were African-American, and the mean age was 78.3 (±11.7) years old. The most common reason for hospitalization was cardiovascular disease and the median length of stay was 9.5 days. Adherence was achieved in 51.6% of patients. Knowing (P<0.01) and prescribing (P<0.01) the complete outpatient regimen upon admission was associated with adherence. Neither class of topical glaucoma medication nor the number of medications was associated with adherence. Doses were most commonly omitted owing to the failure to prescribe (72.3%). Discharge instructions correctly listed the outpatient regimen 54.3% of the time.
Conclusion: Adherence to the topical glaucoma medications was suboptimal during hospitalization; this is likely related to the poor reporting of outpatient regimen upon admission. The effect of hospitalization may be a factor to consider in future studies of adherence and when evaluating glaucoma patients after hospitalization.
Topical glaucoma medication (TGM) is the most commonly used first-line treatment for glaucoma,1,2 the second leading cause of blindness in the United States.1,3 Poor adherence to medications often leads to therapeutic failure,4,5 increased health costs,4,6 and worse clinical outcomes, including poorer intraocular pressure (IOP) control7,8 and greater loss of vision.7,9 Owing to the need for chronic treatment in the management of glaucoma, earlier studies have all been conducted in ambulatory patients. However, it is not uncommon for the glaucoma patients to be hospitalized; for which TGM adherence data are lacking. To the authors’ knowledge, we present the first study to assess adherence during medical hospitalization.
Medical records of all patients discharged with a secondary diagnosis of glaucoma between January 2006 and March 2009 at 2 community-hospitals of Mercy Catholic Medical Centers of Southeastern Pennsylvania were reviewed. The review of medical records showed glaucoma diagnosis codes (ICD-9 codes 365.xx) based on patient self-reporting and earlier medical documentation. Patients were excluded if not being treated with TGM as an outpatient, admitted to a nonmedical service, required emergent medical management, treated with comfort-measures only, hospitalized for <7 days, or evaluated by an ophthalmologist during hospitalization. For patients with multiple admissions, only the admission with the longest length of stay was included.
Four types of medical records were reviewed: (1) Admitting history and physical note, confirming diagnosis of glaucoma, and listing outpatient medications; (2) Physician order forms, listing all medications prescribed during hospitalization; (3) Nursing records, documenting the administration of each TGM dose; and (4) Discharge instructions, listing the TGM regimen to be continued after hospitalization. Data retrieved from the medical records included patient demographics, reason and length of stay for hospitalization, inpatient and outpatient medication regimens, evidence that the TGM regimen was known upon admission, physician prescribing patterns, number and reasons for omitted doses, and TGM regimen listed on discharge instructions.
Hospital admitting and discharge prescribing rates were defined as the proportions of patients correctly prescribed their TGM regimens at the times of admission and discharge, respectively. Administration rate was defined as the ratio of doses administered to doses prescribed. Adherence rate was defined as the ratio of the delivered doses to the expected doses, based on outpatient regimen. On the basis of the earlier studies of adherence,10–12 patients receiving more than equal to 75% of their doses were classified as adherent. Univariable logistic regression was carried out for possible predictors of adherence. Variables with P values <0.20, and not correlated beyond±0.7 Pearson coefficient, underwent multivariable logistic regression; only those with P values <0.05 were considered significant. Statistical analysis was done with SPSS statistical analysis package version 17.0 (SPSS Inc, Chicago, IL). This study was approved by the institutional review board.
A total of 184 patients met the eligibility criteria. Baseline characteristics, for adherent and nonadherent groups are presented in Table 1. A large percentage of patients were African-American (56%). However, age, sex, and race distributions were found to be similar between the groups (P>0.05). Patients hospitalized for neurologic (67%) or gastrointestinal (63%) diseases were more often nonadherent; however, the sample size for each category was small and the differences were not found to be significant (Table 3). Similarly, the number of inpatient systemic medications was included in the multivariable analysis, but not found to be significant and differed most likely because of 2 patients who had a large number (>20) of systemic medications in the adherent group. Mono-TGM therapy was given to 43% of the patients and prostaglandins (69%) were the most commonly prescribed TGM. Multivariable analysis (Table 2) revealed knowing (P<0.01) and prescribing (P<0.01) the complete TGM regimen upon admission were the predictors of adherence.
A summary of measures of adherence during hospitalization is presented in Table 3. The mean (±standard deviation) adherence was 67.3% (±29.4) and the median (IQ1–3) was 75.0% (54.0 to 89.4). Adherence ranged from 0.0% to 100%. The proportion of patients who received at least 75% of their expected doses was 51.6% (95/184). The proportion of patients who received fewer than 50% and 25% of their doses were 20.6% (38/184) and 9.8% (18/184), respectively. Seventeen patients (9.2%) received none of their TGM doses, missing on average 56 (range, 14 to 140) consecutive doses.
The proportion of patients who were prescribed their complete TGM at the time of admission was 51.1% (94/184). Once a TGM had been prescribed, it was administered, on average, 84.8% of the time. After multivariable analysis, knowing the TGM regimen upon admission (OR=3.27; P<0.01) and length of stay (OR=0.18; P<0.01) were associated with prescribing all TGM upon admission and administering at least 75% of the prescribed doses, respectively. Discharge instructions correctly listed TGM regimens to be continued as an outpatient 54.3% (99/184) of the time; no significant associations were identified. Reasons for omitted doses are presented in Table 4. Our sample (n=184) had adequate power (80%;α<0.05), based on post hoc analysis using the χ2 testing, to detect a difference (only those receiving ≥75% were defined as adherent) in the rate of TGM prescribed on admission between adherent (n=95) and nonadherent (n=89) groups and was adjusted for multiple comparison.
Approximately, 38% of Americans hospitalized are over the age of 65 and 24% are over the age of 75.13 Given advanced age is a one of the most important risk factors for primary open-angle glaucoma, glaucoma patients represent a significant number of the millions of Americans hospitalized each year. Although glaucoma is managed by the ophthalmologists in ambulatory patients, primary-care physicians typically control the daily management in affected patients throughout hospitalization. To the authors’ knowledge, this study is the first to present data on TGM adherence during hospitalization.
Only about half (51.6%) of the study patients were found to be adherent. Recent studies that have used similar definitions of adherence (≥75% or 80%) have all reported higher rates (71% to 77%).10–14 Friedman et al15 identified African-American race, extremes of age, depression, and poorer patient health status with lower adherence rates. Situational barriers (eg, difficulty in administering TGM or forgetfulness),7 complex TGM regimens (eg, dose frequency),14,16,17 lower health literacy,18 and limitations in the doctor-patient relationship19 have also been associated with poorer adherence. In this study, demographic factors (age, sex, race) and complexity of TGM regimen were not found to be the predictors of adherence. This disparity could be owing to patient-dependent factors, as earlier described, playing a larger role in the ambulatory setting in which the patients are primarily responsible for obtaining and administering medications. In the hospital setting, however, adherence seems to be more dependent on the provider-dependent factors, where we found adherence to be significantly higher when the complete TGM regimen was known (P<0.01) and prescribed (P<0.01) by the hospital physician upon admission. Institutional limitations also exist, as approximately 10% of the prescribed drops were never administered because they were not on hospital formulary.
The administration of doses was less of a barrier to adherence than prescribing them (Table 4). The most common reason for omitted doses was the failure to prescribe (72.3%). Once prescribed, the most common identifiable reason for omission was the lack of TGM availability. The median administration rate was over 90% and the administration ≥75% was associated with longer length of stay (P<0.01), which would presumably allow greater time to improve the TGM availability.
Limitations of this study include retrospective nature, sample size, and accuracy of physician coding; and to minimize misclassification bias owing to the later, only the patients with a clearly documented history of glaucoma being treated with TGM were included in this study. However, it is plausible that some glaucoma patients on TGM were not identified, resulting in an adherence rate that is actually lower than the one reported herein. Medical records from ophthalmologists were not available and therefore, the TGM were ascertained from the past medical records, pharmacy and/or primary-care physician records, and/or patient self-reporting. This may have resulted in an error in determining the patients’ complete TGM regimen. However, these methods most closely emulate the real-life setting for how all outpatient drug regimens are routinely determined when the patients are hospitalized. Our findings are from a 2-center, community hospital-based study and should not be over-generalized. Strengths of this study include administration of TGM by medically trained professionals (eg, registered nurse), increasing the likelihood of proper placement of TGM onto the eye, and clear documentation of each dose administered (avoiding overestimation of rate commonly seen with self-reporting).
Hospitalized glaucoma patients represent an earlier unrecognized group with suboptimal adherence. Although a quantitative relationship between nonadherence and negative clinical outcome has yet to be established, it is certainly plausible that nonadherence during hospitalization may have had a negative effect; particularly so, in the nearly 10% (18/184) patients who did not receive any TGM, including 5 patients who missed 100 or greater consecutive doses. Such suboptimal adherence may be clinically useful to know in patients presenting with poor IOP control after lengthy or frequent hospitalizations.
Hospitalization may have a negative effect on the compliance even after the patient has been discharged. Nearly 50% (85/184) of the patients were presented with an incorrect TGM regimen on their discharge instructions. This may certainly interfere with the beneficial effects of educating the patients about their TGM regimen20 and having an ophthalmologist provide written instructions of TGM regimens for the patients.21 The effect on persistence, a measure of time to discontinuation,22 cannot be known without further study; however, suboptimal persistence with systemic therapy for other chronic diseases has been observed after hospitalization.23,24
In conclusion, adherence to the TGM during medical hospitalization was found to be suboptimal. When TGM was known, admitting physicians were 3 (OR=3.27) times more likely to prescribe the complete TGM regimen, and adherence was more likely to be achieved (P<0.01). Our findings suggest it may be beneficial for patients to bring their TGM with them to the hospital, providing their complete regimen to the admitting physician, and avoiding the issue of TGM unavailability. Ophthalmologists may want to review the TGM regimens and investigate if the patients were adherent, when evaluating glaucoma patients after being discharged from the hospital.
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