HMO indicates health maintenance organization. A subanalysis was performed for individuals with glaucoma who responded to survey questions regarding self-reported visual disability. Because not all individuals answered these questions, the number of participants in the subanalysis may not add up to the total glaucoma cohort. Costs presented in 2015 US dollars.
Error bars indicate SEs. Costs presented in 2015 US dollars.
eTable 1. Most Common ICD-9 Codes Taken From Inpatient Hospital Claims Data for Patients With Inpatient Hospital Admissions in the Calendar Year
eTable 2. Results of Univariable Logistic Regression to Assess Risk of Events Associated With Glaucoma and Glaucomatous Visual Loss
Prager AJ, Liebmann JM, Cioffi GA, Blumberg DM. Self-reported Function, Health Resource Use, and Total Health Care Costs Among Medicare Beneficiaries With Glaucoma. JAMA Ophthalmol. 2016;134(4):357-365. doi:10.1001/jamaophthalmol.2015.5479
The effect of glaucoma on nonglaucomatous medical conditions and resultant secondary health care costs is not well understood.
To assess self-reported medical conditions, the use of medical services, and total health care costs among Medicare beneficiaries with glaucoma.
Design, Setting, and Participants
Longitudinal observational study of 72 587 Medicare beneficiaries in the general community using the Medicare Current Beneficiary Survey (2004-2009). Coding to extract data started in January 2015, and analyses were performed between May and July 2015.
Main Outcomes and Measures
Self-reported health, the use of health care services, adjusted mean annual total health care costs per person, and adjusted mean annual nonoutpatient costs per person.
Participants were 72 587 Medicare beneficiaries 65 years or older with (n = 4441) and without (n = 68 146) a glaucoma diagnosis in the year before collection of survey data. Their mean age was 76.9 years, and 43.2% were male. Patients with glaucoma who responded to survey questions on visual disability were stratified into those with (n = 1748) and without (n = 2639) self-reported visual disability. Medicare beneficiaries with glaucoma had higher adjusted odds of inpatient hospitalizations (odds ratio [OR], 1.27; 95% CI, 1.17-1.39; P < .001) and home health aide visits (OR, 1.27; 95% CI, 1.13-1.43; P < .001) compared with Medicare beneficiaries without glaucoma. Furthermore, patients with glaucoma with self-reported visual disability were more likely to report depression (OR, 1.47; 95% CI, 1.26-1.71; P < .001), falls (OR, 1.34; 95% CI, 1.09-1.66; P = .006), and difficulty walking (OR, 1.22; 95% CI, 1.02-1.45; P = .03) compared with those without self-reported visual disability. In the risk-adjusted model, Medicare beneficiaries with glaucoma incurred an additional $2903 (95% CI, $2247-$3558; P < .001) annual total health care costs and $2599 (95% CI, $1985-$3212; P < .001) higher costs for nonoutpatient services compared with Medicare beneficiaries without glaucoma.
Conclusions and Relevance
Glaucoma is associated with greater use of inpatient and home health aide services and with higher annual total and nonoutpatient medical costs. Perception of vision loss among patients with glaucoma may be associated with depression, falls, and difficulty walking. Reducing the prevalence and severity of glaucoma may result in improvements in associated nonglaucomatous medical conditions and resultant reduction in health care costs.
Glaucoma is a leading cause of irreversible visual impairment in the United States1 and worldwide2,3 and results in progressive structural and functional damage to the optic nerve. Because the disease affects both central and peripheral vision, patients with glaucoma may experience disability and loss of independence and require rehabilitation or health care services in addition to regular ophthalmologic care. Furthermore, because glaucoma is a disease of elderly persons, its prevalence is expected to rise as the population ages.4
Despite the increasing prevalence of glaucoma, the burden of disease is not well understood. While several studies have assessed the financial costs associated with glaucoma, some have methodological limitations regarding the population studied or the data analyzed.5 Studies that have investigated a subset of patients with glaucoma (eg, those with end-stage glaucoma6) do not capture the entire spectrum of the disease burden. Retrospective medical record reviews7 may provide details on patient-level characteristics but lack information on cost.5 Studies using commercial insurance claims8,9 have limited generalizability because glaucoma is more prevalent among the elderly. Studies using Medicare claims data5,10,11 are ideal for cost-effective analyses from a single-payer perspective. However, Medicare claims data alone may not capture the total effect of glaucoma on patient-reported outcomes, health resource use, and total health care costs.
The objective of this study was to test the hypothesis that Medicare beneficiaries with glaucoma (ie, those with visual disability) would have greater health care use and costs compared with the rest of the Medicare population. Furthermore, the aim was to gain a more comprehensive understanding of associated nonglaucomatous medical conditions, health care use, and costs in individuals with glaucoma and glaucomatous vision loss. Specifically, this study aimed to better understand the risk of emergency department (ED) visits, skilled nursing facility use, home health aide visits, inpatient hospitalizations, falls, depression, difficulty walking, and hip fractures among Medicare beneficiaries with glaucoma and to calculate annual total health care costs from all payers. In addition, to minimize the effect of the cost related to glaucoma management, we calculated the mean nonoutpatient costs (ie, the total health care costs with the exclusion of outpatient payments).
Question: What is the nonophthalmologic economic burden of glaucoma?
Findings: This longitudinal observational study using the Medicare Current Beneficiary Survey showed that glaucoma was associated with significantly higher utilization of inpatient and home health aid services, and higher total and nonoutpatient healthcare costs. Furthermore, self-reported visual disability among glaucoma patients was associated with significantly higher odds of depression, falls, and difficulty walking.
Meaning: Glaucoma is associated with higher use of nonophthalmologic inpatient services and healthcare costs. Perception of visual loss may be a useful screening tool for depression and falls.
This study was conducted using the Medicare Current Beneficiary Survey (MCBS) data set. The MCBS is a nationally representative panel survey of both institutionalized and noninstitutionalized Medicare beneficiaries and has been previously described elsewhere.12 In short, interview data are linked with Medicare claims and detailed use data. The MCBS sample was drawn from an enrollment list of all persons eligible for Medicare coverage and includes a national sample of approximately 12 000 to 16 000 participants each year. The MCBS uses a rotating panel survey design in which each sampled beneficiary is selected as part of a panel and interviewed 3 times per year for 3 full calendar years. For this study, we used the MCBS data for 2004 to 2009. Coding to extract data started in January 2015, and analyses were performed between May and July 2015. Because the MCBS is publicly available and does not contain patient identifiers, this study was exempt from institutional review board review and participant informed consent.
Patients were selected based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes extracted from Medicare claims data. Patients with glaucoma included those 65 years or older with a glaucoma-related diagnosis (ICD-9-CM codes 365.1-365.9) during a health care encounter in the previous year. Patients with a diagnosis of glaucoma suspect or ocular hypertension were excluded from the glaucoma group. To account for any glaucoma-related inpatient admissions, 5 individuals who had a primary, secondary, or tertiary diagnosis of glaucoma (ICD-9-CM code 365) as one of the reasons for hospital admission were excluded from analyses. Patients with other ophthalmic diagnoses were not excluded from the study. Patients with glaucoma were subsequently stratified based on self-reported best-corrected visual disability (“some trouble seeing”) if they reported “a little trouble seeing,” “a lot of trouble seeing,” or “no usable vision.” Individuals younger than 65 years were excluded.
Sociodemographic characteristics were recorded for all beneficiaries, including sex, age, self-reported race/ethnicity, level of education, current employment status, and annual income. Self-reported functional independence was assessed using the instrumental activities of daily living by Lawton and Brody.13
Comorbidities were identified according to self-reported histories of 19 chronic conditions as validated previously in other studies14- 16 using the MCBS data. Self-responses or proxy responses to “Has a doctor ever told you that you have [condition]” were used to assess the presence of hypertension, heart disease, neurological and psychiatric disorders, pulmonary disease, nonskin cancer, diabetes mellitus (all types), osteoporosis, and arthritis. These chronic diseases were chosen because of their prevalence among the Medicare population, as well as their effect on disability and outcomes of interest.15,17 The number of comorbidities was included as a count variable in regression analyses, similar to other studies,16 because of significant correlation between comorbidities and our outcomes of interest.
Annual medical costs were derived from the total cost data obtained from the MCBS files. These files provide complete expenditures on all health care services,12 including outpatient, inpatient, institutional, medical professional, prescribed medicine, hospice, home health agency, and facility events. Furthermore, the MCBS includes data from all payment sources, including Medicare, Medicaid, Veterans Affairs, Medicare Advantage, private health maintenance organization, individually purchased insurance, employer-sponsored insurance, and out-of-pocket expenses. For the purposes of this analysis, we calculated the mean annual total health care costs, which include payments from all health care services and payers as listed above. In addition, to minimize bias related to the increased outpatient costs of glaucoma diagnosis and management, we also calculated the mean health care costs with the exclusion of outpatient payments (nonoutpatient costs), in which all annual outpatient costs were deducted from annual total costs. All costs were adjusted for inflation using the medical care Consumer Price Index and are presented in 2015 US dollars.
For cost, the main outcome of interest was the mean annual total health care costs and the mean nonoutpatient health care costs. For health care use, the main outcomes were inpatient hospitalizations, ED visits, home health aide visits, and skilled nursing facility use, all of which were measured in the calendar year and derived from claims data. In addition, self-reported falls, depression, and difficulty walking in the past year, as well as lifetime history of hip fractures, were evaluated from survey data.
Demographics and clinical characteristics of the entire MCBS cohort 65 years or older with vs without a diagnosis of glaucoma were determined. Statistical differences in demographics were assessed using the χ2 test (for categorical variables) or the 2-sample t test (for continuous variables). Covariables that were significantly different between groups were considered in the multivariable model to produce the best fit for all multivariable regression analyses. These covariables were sex, age, race/ethnicity, education, current employment status, number of medical comorbidities, and the Lawton Index, which measures the ability to perform independent activities of daily living.
Logistic regression analyses were performed to measure the odds of health outcomes (binary data) between groups. Negative binomial distribution was used to assess the incidence rate ratio (IRR) of a health outcome (count data) with an associated claim. Multivariable generalized linear models (GLMs) were run to compare the total costs between study groups. The GLM was constructed using log transformation and gamma distribution, which has been found to be a suitable model for expenditure data.18 Risk-adjusted cost estimates by group were derived from the multivariable GLM.
All regressions included robust SE calculations.19 Because participants were interviewed each year during their participation in the survey, a repeated-measures analysis was performed to account for correlated outcomes. Glaucoma was considered an independent predictor for all analyses. Statistical analyses were conducted using a software program (Stata, version 13; StataCorp LP).
Table 1 and Table 2 list characteristics of the MCBS participants in the study. Our study included 72 587 MCBS survey respondents 65 years or older. Among these individuals, 6.1% had a glaucoma diagnosis in the previous year. Respondents with glaucoma were older (mean age, 79.5 vs 76.7 years; P < .001) and comprised more individuals of black race/ethnicity (11.1% vs 7.8%, P < .001) compared with respondents without glaucoma. The mean number of comorbidities was higher in the glaucoma group compared with the nonglaucoma group (3.4 vs 3.1, P < .001), and the mean Lawton Index was lower (indicating lower functioning) in the glaucoma group (4.8 vs 5.0, P < .001). The percentages of self-reported best-corrected visual disability were 39.4% in the glaucoma group and 29.1% in the nonglaucoma group (P < .001). Patients with glaucoma with self-reported visual disability also tended to be older (mean age, 80.4 vs 78.9 years; P < .001), be of black race/ethnicity (11.7% vs 10.8%, P = .67), and have more comorbidities (3.7 vs 3.2, P < .001) compared with those without self-reported visual disability. For those patients with an inpatient hospitalization in the calendar year, the reasons for admission are listed in eTable 1 in the Supplement.
The results of multivariable analyses are summarized in Table 3 (the results from univariable analyses are listed in eTable 2 in the Supplement). After adjusting for covariables, patients with glaucoma were 27.4% more likely to have a home health aide visit (OR, 1.27; 95% CI, 1.13-1.43; P < .001) or an inpatient hospitalization (OR, 1.27; 95% CI, 1.17-1.39; P < .001) in the calendar year compared with patients without glaucoma (Table 3). Furthermore, the numbers of home health aide visits (IRR, 1.35; 95% CI, 1.04-1.75; P = .03) and inpatient hospitalizations (IRR, 1.20; 95% CI, 1.11-1.30; P < .001) were higher among the glaucoma cohort. There were no significant differences in the odds of staying in a skilled nursing facility (OR, 1.15; 95% CI, 0.97-1.36; P = .12) or visiting the ED (OR, 0.91; 95% CI, 0.79-1.10; P = .20) between those with vs without glaucoma (Table 3).
In the adjusted model, the overall cohort of Medicare beneficiaries with glaucoma reported similar rates of difficulty walking (OR, 1.08; 95% CI, 0.98-1.19; P = .11), falls (OR, 0.94; 95% CI, 0.85-1.05; P = .26), and depression (OR, 0.96; 95% CI, 0.89-1.04; P = .31) in the past year compared with beneficiaries without glaucoma (Table 3). However, the subset of beneficiaries with glaucoma with visual disability was more likely to report all 3 behaviors compared with beneficiaries with glaucoma without visual disability, including difficulty walking (OR, 1.22; 95% CI, 1.02-1.45; P = .03), falls (OR, 1.34; 95% CI, 1.09-1.66; P = .006), and depression (OR, 1.47; 95% CI, 1.26-1.71; P < .001). There were no significant differences in lifetime history of hip fractures between beneficiaries having glaucoma with vs without visual disability (OR, 0.87; 95% CI, 0.60-1.26; P = .46).
The mean annual total costs were higher for patients with glaucoma compared with patients without glaucoma ($16 760 vs $13 094, P < .001) and remained higher after the exclusion of outpatient costs ($14 273 vs $11 024, P < .001). Likewise, the mean annual total costs were greater among the subset of Medicare beneficiaries with glaucoma with visual disability compared with those without visual disability ($18 073 vs $15 829, P = .009), as well as after the exclusion of outpatient costs ($15 428 vs $13 448, P = .01). Most costs were incurred by Medicare, followed by out-of-pocket payments and employer-sponsored insurance coverage (Figure 1A). The highest percentage of costs was devoted to physician services, followed by inpatient care and prescription medications (Figure 1B and Figure 2).
After adjusting for socioeconomic factors and comorbidities, patients with glaucoma (regardless of visual disability) had higher mean total and nonoutpatient costs compared with those without glaucoma (total cost, $18 073 vs $13 094; P < .001 for those with self-reported visual disability and total cost, $15 829 vs $13 093; P < .001 for those without self-reported visual disability). After adjusting for covariables, Medicare beneficiaries with glaucoma incurred predicted $2903 (95% CI, $2247-$3558; P < .001) higher mean annual total health care costs from all sources compared with Medicare beneficiaries without glaucoma. Costs remained higher for Medicare beneficiaries with glaucoma after the exclusion of outpatient payments ($2599; 95% CI, $1985-$3212; P < .001). In the risk-adjusted model, there was no significant difference in predicted costs among Medicare beneficiaries with glaucoma with vs without visual disability (−$102; 95% CI, −$1635 to $1430; P = .90).
The disease burden of glaucoma in the United States is poorly understood. After controlling for covariables, this study found that Medicare beneficiaries with glaucoma were more likely to have inpatient hospitalizations and require home health aide visits compared with beneficiaries without glaucoma. Self-reported visual disability among beneficiaries with glaucoma was associated with greater odds of self-reported depression, difficulty walking, and falls. Furthermore, diagnosed glaucoma was associated with significantly higher mean total and nonoutpatient costs compared with beneficiaries without glaucoma, and costs were higher among those with visual disability. These findings suggest that beneficiaries with glaucoma are more likely to have worse ophthalmologic and nonophthalmologic outcomes, resulting in greater health care use and significant additional costs to society.
The association between glaucoma and the use of health care services is not clearly established in the literature. Using Centers for Medicare & Medicaid Services claims data, Kymes et al11 found no association between glaucoma and nursing home admission or home health service use. On the other hand, Bramley et al10 found that individuals with vision loss from glaucoma were more than twice as likely to be admitted to a nursing home compared with those without vision loss. Differences in these study findings and ours are likely because of differences in methods (eg, the populations surveyed and the use of claims data rather than survey data).
Mobility disturbances are frequently reported by patients with glaucoma20,21 and have been highly correlated with the degree of peripheral vision loss.22- 24 By extension, poor self-reported vision has been associated with increased odds of falls independent of visual acuity.25 Likewise, glaucoma-related visual field loss has been associated with greater fear of falling.26 Despite the correlation, a causal relationship between subjective visual impairment and falls is not clear. While the preponderance of data suggests that vision loss may result in imbalance and resultant falls,27- 30 it is possible that an acute event such as a fall may increase a patient’s awareness of his or her visual limitations. This rationale may in part explain our finding among the Medicare population that patients with glaucoma without visual disability reported fewer falls than patients without glaucoma.
Likewise, subjective vision loss has been associated with worse psychosocial functioning, which is defined as the psychological and social effects of a disease on a patient.31 The Los Angeles Latino Eye Study32 found an association between self-reported visual function and self-reported depression. Jampel et al33 also observed that subjective visual function in patients with newly diagnosed glaucoma was correlated with poor mood, while objective measures such as visual acuity and visual fields were not. Using a glaucoma-specific survey (Glaucoma Quality of Life 36), Chan et al34 found that glaucoma-induced visual acuity reduction and visual field loss were associated with worse psychosocial functioning even at early stages of the disease. Unlike the glaucoma-specific survey, the MCBS questionnaire was not designed to detect psychological distress. Despite this limitation, we found that self-reported visual disability in patients with glaucoma was associated with perceived depression.
Few glaucoma-specific studies investigated the association between costs and vision loss severity. Kymes et al11 created a Markov model using both Medicare and Medicaid claims data to compare costs between those with vs without primary open-angle glaucoma (POAG). They found that the expected lifetime cost for patients with POAG was $1688 higher than that for individuals without POAG. In contrast to our study, their study was a cost-effectiveness analysis that evaluated lifetime cost from a single payer. Bramley et al10 used Medicare claims data to compare Medicare expenditures between patients with glaucoma with either moderate, severe, or no vision vs normal vision. In general, our mean annual total costs were similar to theirs, despite calculating costs from all sources, including out-of-pocket payments and private insurance. Furthermore, Bramley et al used ICD-9-CM codes for vision loss severity, while we used self-reported visual disability. Future studies should assess whether physician assessment or patient self-report is a better predictor of daily visual function.
Our study used the MCBS data set, which offers several benefits over Medicare claims data alone. First, the MCBS asks survey participants about their health and physical functioning even for conditions for which the patient did not seek care. This inclusion provides useful information because many conditions (eg, difficulty walking or perceived sadness) may not be captured by claims data. Second, the MCBS follows Medicare beneficiaries in and out of long-term care and provides valid estimates of nursing home use and expenditures. On the other hand, Medicare provides limited coverage for nursing home benefits and home health aide visits. The MCBS also includes data on ED use, while Medicare claims data do not have unique ED visit claim codes. Third, while Medicare claims studies are limited to services and resultant costs incurred by a single payer, the MCBS incorporates costs from all payers, including those not covered by Medicare. These data allow researchers to study the full spectrum of both private and public sector health care use and costs.35
The study has several limitations. First, we did not evaluate severity of glaucoma using objective measures but rather through self-report of visual impairment. Although this protocol may be perceived as a limitation, subjective approaches capture the quality of vision, which cannot be measured by objective measures alone. However, there is a possibility that self-reported poor vision in patients with glaucoma was the result of an ophthalmic condition other than glaucoma. Furthermore, individuals with progressive, peripheral vision loss from glaucoma may not sense vision loss until their central vision is affected. This possibility may have contributed to underreporting of vision loss, which may have biased our results when comparisons were made within the glaucoma cohort based on the degree of visual disability. Second, our control group consisted of the general MCBS population, which may include individuals with undetected glaucoma. However, any resultant bias would minimize differences between the glaucoma and control groups. Despite this limitation, we found significant differences in several outcomes and costs between those with glaucoma and the general Medicare population. Third, although we included payments from all sources, we did not include indirect costs such as reduced productivity and wages for the patients and their caregivers, which are difficult to measure but could amount to substantially larger societal costs.
A better understanding of medical costs associated with glaucoma can aid policy makers in articulating an economic argument for reducing the burden of the disease. This study found that among Medicare beneficiaries a diagnosis of glaucoma is associated with greater use of inpatient and home health aide services and with higher annual total and nonoutpatient costs. Self-reported visual impairment was a strong indicator of worse health functioning. Patients with glaucoma, in particular those who report worse vision, should be monitored for other medical conditions. Physicians should consider asking patients about their perception of vision loss as a surrogate screening tool for depression and falls.
Submitted for Publication: August 10, 2015; final revision received October 29, 2015; accepted November 18, 2015.
Corresponding Author: Dana M. Blumberg, MD, MPH, Bernard and Shirlee Brown Glaucoma Research Laboratory, Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Medical Center, 635 W 165th St, New York, NY 10032 (firstname.lastname@example.org).
Published Online: January 7, 2016. doi:10.1001/jamaophthalmol.2015.5479.
Author Contributions: Ms Prager and Dr Blumberg had full access to all the data in the study and take responsibility for the integrity of the data and accuracy of the data analyses.
Study concept and design: Prager, Blumberg.
Acquisition, analysis, or interpretation of data: Prager, Blumberg.
Drafting of the manuscript: All authors.
Critical revision of the manuscript for important intellectual content: All authors.
Administrative, technical, or material support: All authors.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported.
Funding/Support: This project is supported by an unrestricted grant from the glaucoma research fund at the Edward S. Harkness Eye Institute, Columbia University Medical Center (Dr Blumberg).
Role of the Funder/Sponsor: The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.