Jonathan C. Javitt

Model of Complications of NIDDM: II. Analysis of the health benefits and cost-effectiveness of treating NIDDM with the goal of normoglycemia

OBJECTIVE To analyze the health benefits and economics of treating NIDDM with the goal of normoglycemia. RESEARCH DESIGN AND METHODS Incidence-based simulation model of NIDDM was used. Hazard rates for complications were adjusted for glycemia using risk gradients from the Diabetes Control and Complications Trial. Treatment costs were estimated from national survey data and clinical trials. Incremental costs and benefits were expressed in present value dollars (3% discount rate). Life-years were adjusted for quality of life, yielding quality-adjusted life-years (QALYs). RESULTS Comprehensive treatment of NIDDM that maintains an HbA1c value of 7.2% is predicted to reduce the cumulative incidence of blindness, end-stage renal disease, and lower-extremity amputation by 72, 87, and 67%, respectively. Cardiovascular disease risk increased by 3% (no effect of treating glycemia is assumed). Life expectancy increased 1.39 years. The cost of treating hyperglycemia increased by almost twofold, which is partially offset by reductions in the cost of complications. The estimated incremental cost/QALY gained is

National study of cataract surgery outcomes: Variation in 4-month postoperative outcomes as reflected in multiple outcome measures

16,002. Treatment is more cost-effective for those with longer glycemic exposure (earlier onset of diabetes), minorities, and those with higher HbA1c under standard care. CONCLUSIONS The incremental effectiveness of treating NIDDM with the goal of normoglycemia is estimated to be ∼

Diabetes, Intraocular Pressure, and Primary Open-angle Glaucoma in the Baltimore Eye Survey

16,000/QALY gained, which is in the range of interventions that are generally considered cost-effective.

The Cause-specific Prevalence of Visual Impairment in an Urban Population: The Baltimore Eye Survey

BACKGROUNDnAlthough ophthalmologists have long recognized that visual acuity alone is an inadequate measure of visual impairment, the need for and outcomes of cataract surgery historically have been assessed in terms of visual acuity.nnnPURPOSEnTo examine the relation among different cataract surgery outcome measures, including a 14-item instrument designed to measure functional impairment caused by cataract (the VF-14), at 4 months after cataract surgery.nnnMETHODSnThe authors performed a longitudinal study of 552 patients undergoing first eye cataract surgery by 1 of 75 ophthalmologists practicing in Columbus, Ohio, St. Louis, Missouri, or Houston, Texas. Patients were interviewed, and clinical data were obtained preoperatively (July 15, 1991-March 14, 1992) and 4 months postoperatively.nnnRESULTSnThe percentage of patients judged to be improved at 4 months after cataract surgery varied by the outcome measure used: Snellen visual acuity (96%); VF-14 score (89%); satisfaction with vision (85%); self-reported trouble with vision (80%); and Sickness Impact Profile score (67%). The change in patients ratings of their trouble with vision and their satisfaction with vision were correlated more strongly with the change in VF-14 score than with the change in visual acuity (operated eye or better eye). The average change in VF-14 score was unrelated to the preoperative visual acuity in the eye undergoing surgery.nnnCONCLUSIONnEstimates of the proportion of patients benefiting from cataract surgery vary with the outcome measure used to measure benefit. Change in VF-14 score, a measure of functional impairment related to vision, may be a better measure of the benefit of cataract surgery than change in visual acuity.

Risk Factors for Retinal Detachment after Cataract Surgery: A Population-based Case-Control Study

BACKGROUNDnThe association of diabetes with primary-open angle glaucoma (POAG) has been controversial and often confused by varying definitions of both diabetes and POAG. The purpose of this study is to evaluate this association in a population-based sample of subjects from the Baltimore Eye Survey.nnnMETHODSnA stratified sample of residents in 16 cluster areas of east Baltimore was recruited for a detailed ophthalmologic screening examination. A total of 5308 black subjects and white subjects participated. Of these participants, 161 received a diagnosis of POAG. During a detailed interview with each subject, diabetes was defined based on a reported history of diabetes. Persons with diabetes were classified as insulin-users and noninsulin-users based on their current method of treatment.nnnRESULTSnDiabetes was highly prevalent in this population, with 10.6% of white subjects and 17.2% of black subjects reporting a positive history. Diabetes was associated with higher intraocular pressure, but differences were not large (means, 17.4, 18.0, and 17.8 mmHg) among subjects without diabetes, those with diabetes who were not using insulin, and those with diabetes who were using insulin, respectively. Diabetes was not associated with POAG (age-race-adjusted odds ratio, 1.03; 95% confidence interval, 0.85, 1.25). This was true for both types of diabetes. Persons whose POAG had been diagnosed before the examination showed a positive association with diabetes (odds ratio, 1.7, 95% confidence interval, 1.03, 2.86), indicating that selection bias could explain the positive results of previous clinic-based investigations.nnnCONCLUSIONnThere is no evidence from this population-based investigation that supports an association between diabetes and POAG.

National Outcomes of Cataract Extraction: Retinal Detachment and Endophthalmids after Outpatient Cataract Surgery

BACKGROUNDnWhereas population-based data on the causes of bilateral blindness have been reported, little information is available on the distribution of causes of central vision loss less severe than the criteria used to define legal blindness. This visual impairment is responsible for a high proportion of eye care service use and results in important reductions in functional status.nnnMETHODSnData from the Baltimore Eye Survey were used to estimate the cause-specific prevalence of visual impairment (best-corrected visual acuity worse than 20/40 but better than 20/200) among black and white residents of east Baltimore who were 40 years of age or older. Eligible subjects underwent a screening examination at a neighborhood location and, for those whose best-corrected visual acuity was less than 20/30, a definitive ophthalmologic examination at the Wilmer Eye Institute.nnnRESULTSnThe prevalence of visual impairment was 2.7% in whites and 3.3% in blacks; the age-adjusted relative prevalence (B/W) was 1.75 (P = 0.01). The leading causes of visual impaired eyes were cataract (35.8%), age-related macular degeneration (14.2%), diabetic retinopathy (6.6%), glaucoma (4.7%), and other retinal disorders (7.3%). Cataract, diabetic retinopathy, and glaucoma were more common as a cause of visual impairment among blacks, whereas macular degeneration was more frequent among whites. More than 50% of all subjects had the potential for improvement in vision with appropriate surgical intervention.nnnCONCLUSIONnVisual impairment is a prevalent condition among inner city adults 40 years of age or older. The distribution of causes suggests that improvements in the visual health of the population could be achieved with more effective delivery of efficacious ophthalmologic care.

Predictors of Outcome in Patients Who Underwent Cataract Surgery

PURPOSEnPrevious analyses of Medicare claims data, as well as clinical series, have suggested that performance of neodymium:YAG (Nd:YAG) laser posterior capsulotomy after extracapsular cataract surgery increases significantly the risk of retinal detachment. However, methodologic problems with previous research limit the strength of conclusions that can be drawn from these earlier studies. This study was designed to resolve those methodological limitations while using a population-based approach for assessment of the independent association between the performance of Nd:YAG laser posterior capsulotomy and pseudophakic retinal detachment.nnnMETHODSnA nested case-control study was conducted. Medicare beneficiaries who had undergone extracapsular cataract extraction from 1988 to 1990 were identified from a 5% sample of Medicare claims data. Within this cohort, people who were diagnosed or treated for retinal detachment during the years 1988 through 1991 (cases) were identified from Medicare records. Four controls were matched to each case of retinal detachment using an incidence density design. Providers of the patients cataract and retinal surgery were contacted and asked to provide clinical data for all cases and controls that they had treated.nnnRESULTSnSeven hundred six cases of retinal detachment were originally identified from Medicare records. After exclusions due to ineligibility, a total of 291 cases and 870 matched controls were available for analysis. Conditional logistic regression models showed that a number of factors were associated independently with an excess risk of retinal detachment after cataract surgery. These included Nd:YAG laser capsulotomy (odds ratio [OR] = 3.8; 95% confidence interval [CI], 2.4-5.9), a history of retinal detachment (OR = 2.7; 95% CI, 1.2-6.1), a history of lattice degeneration (OR = 6.6; 95% CI, 1.6-27.1), axial length (OR = 1.21/mm; 95% CI, 1.03-1.43), refractive error (OR = 0.92/diopter; 95% CI, 0.88-0.95), and a history of ocular trauma after cataract surgery (OR = 6.1; 95% CI, 4.3-28.2).nnnCONCLUSIONnPerformance of Nd:YAG laser posterior capsulotomy is associated with a significantly elevated risk of retinal detachment in patients who have undergone extracapsular cataract extraction. Other independent risk factors for retinal detachment include axial length, myopia, posterior capsular rupture during surgery, history of retinal detachment or lattice degeneration, and ocular trauma after cataract surgery.

Using Medicare Claims for Outcomes Research

Background: A near-total shift to cataract extraction on an outpatient basis occurred as a result of an administrative ruling by the Health Care Financing Administration. No national study has been conducted to assess the possible effects of that decision on clinical outcomes of surgery. The authors compared the rates of retinal detachment (RD) repair and hospitalization for endophthalmitis after extracapsular cataract extraction (ECCE) (including phacoemulsification) in 1986 and 1987 with those following inpatient cataract extraction in 1984. Methods: Using the 5% random sample of Medicare beneficiaries, we analyzed the claims of all individuals 66 years of age or older who underwent ECCE by nuclear expression or phacoemulsification in 1986 and 1987. A total of 57,103 patients were identified and followed to the end of 1988. Cumulative probability of RD repair and hospitalization for endophthalmitis was calculated by standard lifetable methods. These findings were compared with the cumulative probability of the same complications in a cohort of 330,000 patients who underwent cataract extraction on an inpatient basis in 1984. Results: In the 1986-to-1987 cohort, the cumulative probability of RD within 3 years after cataract surgery was 0.81% and the cumulative probability of endophthalmitis within 1 year was 0.08%. The rate of RD is similar to that which we previously reported for 330,000 patients who underwent inpatient surgery in 1984, but the rate of endophthalmitis is significantly lower in the 1986-to-1987 outpatient cohort (0.08% versus 0.12%; z = 2.42; P = 0.01). Conclusions: The shift to outpatient cataract surgery was accompanied by no significant increase in the probability of RD repair and possibly a significant decrease in the rate of hospitalization for endophthalmitis.

Variation in Cataract Surgery Practice and Clinical Outcomes

PURPOSEnTo identify preoperative patient characteristics associated with a lack of improvement on one or more measures 4 months after cataract surgery.nnnMETHODSnThe authors collected preoperative and 4-month postoperative information on 552 patients undergoing first-eye cataract surgery from the practices of 72 ophthalmologists in three cities. The principal outcomes assessed were (1) Snellen visual acuity, (2) a cataract-related symptom score (possible range: 0, 0 of 6 symptoms present or bothersome, to 18, all 6 symptoms very bothersome), and (3) a measure of functional impairment in patients with cataract--the VF-14 score (possible range: 0, inability to perform any of the applicable activities, to 100, no difficulty performing any of the applicable activities). Multiple logistic regression was used to assess the association between preoperative patient characteristics and failure to improve on one or more outcome measures. Multiple linear regression was used to estimate the adjusted rate of lack of improvement in one or more outcome measures for one group of patients compared with another.nnnRESULTSnAlthough 91 patients (16.5%) failed to improve on one or more of the outcome measures assessed, only 2 (0.4%) failed to improve on all three measures. The 91 patients who did not improve on at least one measure were approximately one sixth as likely to be satisfied with their vision postoperatively as the 461 patients who improved on all three outcome measures. Preoperative age of 75 years of age or older, VF-14 score of 90 or higher, cataract symptom score of 3 or lower, and ocular comorbidity (glaucoma, diabetic retinopathy, or age-related macular degeneration) were associated independently with increased likelihood of not improving on one or more measure (odds ratio: 3.57, 2.10, 3.29, and 2.16, respectively). The mean adjusted rate of failure to improve on at least one of the outcome measures ranged from 20.5% to 26.5% for patients with these preoperative characteristics compared with 8.8% to 13.8% for those patients without them. The preoperative level of Snellen visual acuity was not associated with the likelihood of not improving on one or more of the outcomes assessed.nnnCONCLUSIONSnThe authors conclude that specific preoperative characteristics (age, comorbidity, cataract symptom score, and VF-14 score) are independent predictors of patient outcome after cataract surgery.

National Outcomes of Cataract Extraction I: Retinal Detachment after Inpatient Surgery

Medicare claims databases have several advantages for use in constructing episodes of care for outcomes research. They are population-based, relatively inexpensive to obtain, include large numbers of cases, and can be used for long-term follow-up. However, the sheer size of these claims databases, along with their primarily administrative (as opposed to clinical) nature, requires that researchers take special care in using them. The 10 PORTs using Medicare claims provided information on their approach to several key issues in working with these data, including: 1) identifying the index cases or patient cohorts to be studied; 2) defining the length of the episode; and 3) measuring outcomes. This paper reports the experience and knowledge gained by these PORTs in using these claims to create and analyze episodes of care.