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Biomedical subjects

A M Connell

Publications and source records attributed to A M Connell.

At least 19 recordsLinked to original sources
PubMed2001

Prevalence and causes of visual impairment in The Barbados Eye Study.

OBJECTIVE: To determine the prevalence and causes of low vision and blindness in a predominantly black population. DESIGN: Population-based prevalence study of a simple random sample of Barbados-born citizens aged 40 to 84 years. PARTICIPANTS: Four thousand seven hundred nine persons (84% participation). METHODS: The standardized protocol included best-corrected visual acuity (with a Ferris-Bailey chart), automated perimetry, lens gradings (LOCS II), and an interview. Participants with visual acuity of worse than 20/30, other positive findings, and a 10% sample also had an ophthalmologic examination that evaluated the cause and extent of vision loss (resulting from that cause), if any. MAIN OUTCOME MEASURES: Low vision and blindness were defined as visual acuity in the better eye between 6/18 and 6/120 and visual acuity worse than 6/120, respectively (World Health Organization [WHO] criteria). RESULTS: Of the 4631 participants with complete examinations, 4314 (93%) reported their race as black, 184 (4%) reported their race as mixed (black and white), and 133 (3%) reported their race as white or other. Low vision was found in 5.9% of the black, 2.7% of the mixed, and 3.0% of white or other participants. Bilateral blindness was similar for black and mixed race participants (1.7% and 1.6%, respectively) and was not found in whites. Among black and mixed participants, the prevalence of low vision increased with age (from 0.3% at 40-49 years to 26.8% at 80 years or older). The prevalence of blindness was higher (P < 0.001) for men than women at each age group (0.5% versus 0.3% at ages 40-49 and 10.9% versus 7.3% at 80 years or more). Sixty percent of blindness was due to open-angle glaucoma and age-related cataract, each accounting for more than one fourth of cases. Other major causes were optic atrophy or neuropathy and macular and other retinal diseases. Few cases of blindness were due to diabetic retinopathy (1.4%), and none were due to age-related macular degeneration. CONCLUSIONS: Using the WHO criteria, prevalence of visual impairment was high in this African-origin population, particularly at older ages. Most blindness was due to open-angle glaucoma and cataract, with open-angle glaucoma causing a higher proportion of blindness than previously reported. The increased prevalence of blindness in men may be due to the increased male prevalence of glaucoma in this population and warrants further investigation. Results underline the need for blindness prevention programs, with emphasis on effective treatment of age-related cataract and enhancing strategies for early detection and treatment of open-angle glaucoma.

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PubMed2001

Incidence of open-angle glaucoma: the Barbados Eye Studies. The Barbados Eye Studies Group.

OBJECTIVE: To measure the 4-year risk of open-angle glaucoma (OAG) in a black population. DESIGN: Population-based cohort study with 4 years of follow-up. SETTING: Simple random sample of residents of Barbados, West Indies, aged 40 years or older. PARTICIPANTS: A total of 3427 members of the cohort (85% of those eligible). MAIN OUTCOME MEASURE: Development of glaucoma visual field defects and optic disc damage, confirmed by automated perimetry, independent fundus photographic gradings, and standardized ophthalmologic examinations. RESULTS: The 4-year risk of OAG in black participants was 2.2% (95% confidence interval, 1.7%-2.8%), based on 67 newly developed cases of OAG. Incidence rates increased from 1.2% at ages 40 to 49 years to 4.2% at ages of 70 years or more, tending to be higher in men than women (2.7% vs 1.9%). About half of the incident cases were undiagnosed previously, and the rest were receiving OAG treatment. Of the 67 new cases of OAG, 32 had intraocular pressure of 21 mm Hg or less at baseline (1.2% incidence) and 35 had higher pressures (9% incidence). Risk was highest among persons classified as having suspect OAG at baseline (26.1%), followed by those with ocular hypertension (4.9%) and lowest in the remaining population (0.8%). CONCLUSIONS: This longitudinal study provides new information on OAG risk, as well as the first incidence measurement in a black population. Although intraocular pressure increased risk, about half of the new cases had baseline pressures of 21 mm Hg or less. Results substantiate the high OAG risk in the population of African origin, especially in older adults; the relative role of intraocular pressure; and the considerable underdetection of new disease after 4 years of follow-up.

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PubMed2000

Incidence and progression of lens opacities in the Barbados Eye Studies.

OBJECTIVE: To provide 4-year cumulative incidence and progression rates of age-related lens opacities in a population > or =40 years of age, which is mainly of African origin. DESIGN: Cohort study that reexamined surviving members of the population-based Barbados Eye Study 4 years after baseline. PARTICIPANTS: Three thousand four hundred twenty-seven members of the Barbados Eye Study cohort (85% of those eligible). MAIN OUTCOME MEASURES: The Lens Opacities Classification System II (LOCS II) was used at the slit lamp. Cumulative incidence was defined as the development of any nuclear, cortical or posterior subcapsular (PSC) opacities (LOCS II scores > or =2) among persons without that opacity type at baseline. Cumulative progression was defined by at least two-step increases in scores among persons with preexisting lens opacities. RESULTS: The incidence of cortical opacities was about five times greater in black than white participants (age-gender adjusted relative risk = 4.7; 95% confidence interval: 1.9-11.4). In the black population, the 4-year incidence rates were 22.2% (20.4%-24.0%) for any cortical, 9.2% (8.2%-10.4%) for any nuclear, and 3.3% (2.7%-4.0%) for any PSC opacities; rates increased greatly with age. Four-year progression rates were 12.5% for cortical, 3.6% for nuclear, and 23.0% for PSC opacities, without consistent pattern by age. Women had a greater risk of cortical and nuclear opacities (P<0.05) than men and greater progression of nuclear opacities. The presence of PSC opacities at baseline seemed to at least double the incidence and progression rates of other opacities. In persons initially opacity free, single cortical opacities were the predominant type to develop at followup. Visual acuity loss frequently accompanied incident opacities. CONCLUSIONS: This longitudinal study provides new population-based data on the natural history of lens opacities. Incidence and progression of opacities, especially of cortical opacities, were high. After 4 years of followup, 1 in 4 to 5 participants developed cortical opacities, 1 in 11 developed nuclear opacities, and 1 in 30 developed PSC opacities. The information obtained attests to the public health impact of age-related cataract, as well as its extent, in this and similar black populations.

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PubMed1999

Diabetes, hypertension, and central obesity as cataract risk factors in a black population. The Barbados Eye Study.

OBJECTIVE: The increased cataract prevalence of black populations, especially of cortical cataract, remains unexplained. The authors evaluate the relationships of diabetes, hypertension, and obesity patterns to lens opacities, by age, among 4314 black participants in the Barbados Eye Study. DESIGN AND PARTICIPANTS: Prevalence study of a random sample of the Barbados population, ages 40 to 84 years (84% participation). MAIN OUTCOME MEASURES: Associations with age-related lens changes (grade > or = 2 in the Lens Opacities Classification System II at the slit lamp) were evaluated in logistic regression analyses by age (persons < 60 years and > or = 60 years). Results are presented as odds ratios (OR) with 95% confidence intervals. RESULTS: Of the 1800 participants with lens changes, most had cortical opacities. Diabetes history (18% prevalence) was related to all lens changes, especially at younger ages (age < 60 years: OR = 2.23 [1.63, 3.04]; age > or = 60 years: OR = 1.63 [1.22, 2.17]). Diabetes also increased the risk of cortical opacities (age < 60 years: OR = 2.30 [1.63, 3.24]; age > or = 60 years: OR = 1.42 [1.03, 1.96]); additional risk factors were high diastolic blood pressure (age < 60 years: OR = 1.49 [1.00, 2.23]) and higher waist/hip ratio (all ages: OR = 1.36 [1.00, 1.84]). Diabetes was also related to posterior subcapsular opacities. Glycated hemoglobin levels were positively associated with cortical and posterior subcapsular opacities. Overall, 14% of the prevalence of lens changes could be attributed to diabetes. CONCLUSIONS: The high prevalence of cortical opacities was related to diabetes, hypertension, and abdominal obesity, which also are common in this and other black populations. Interventions to modify these risk factors, especially in populations in which they are highly prevalent, may have implications to control visual loss from cataract, which is the first cause of blindness worldwide.

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PubMed1999

Diabetic retinopathy in a black population: the Barbados Eye Study.

OBJECTIVE: The distribution of diabetic retinopathy in black populations is largely unknown. The authors present retinopathy data from the predominately black participants of the Barbados Eye Study (BES). DESIGN AND PARTICIPANTS: Prevalence study of 4631 participants based on a random sample of the Barbados population 40 to 84 years of age (84% participation). MAIN OUTCOME MEASURES: Diabetes was defined as self-reported history of physician-diagnosed diabetes or glycosylated hemoglobin greater than 10% (>2 standard deviations above the population mean of persons without a diabetes history). Retinopathy was assessed by independent gradings of 30 degrees color stereo fundus photographs of the disc and macula. RESULTS: Diabetes was present in 19.4% of black (n = 4314), 15.2% of mixed (black and white; n = 184), and 7.5% of white/other (n = 133) self-reported racial groups. In the black/mixed population, regardless of diabetes status, the prevalence of retinopathy was 5.9%. In the 636 black and mixed participants with diabetes, the prevalence of retinopathy was 28.5%: 19.8% had minimum changes, 7.7% had moderate changes, and 0.9% had severe retinopathy. Clinically significant macular edema (CSME) was found in 8.6% of those with diabetes. CONCLUSIONS: In the population of African origin, approximately 1 in 17 persons had retinopathy. Among those with diabetes, 28.5% had retinopathy and 8.6% had CSME. These results highlight the clinical and public health relevance of diabetic retinopathy in the black population.

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PubMed1997

Prevalence of lens opacities in the Barbados Eye Study.

OBJECTIVE: To present population-based data on type and extent of age-related lens opacities in the predominantly black population of the Barbados Eye Study. DESIGN: Prevalence study. SETTING AND PARTICIPANTS: The Barbados Eye Study included 4709 participants (84% of those eligible), who were identified from a random sample of Barbadian-born citizens aged 40 to 84 years. DATA COLLECTION: Lens gradings at the slit lamp, obtained with the use of the Lens Opacities Classification System II. MAIN OUTCOME MEASURE: Prevalence of posterior subcapsular, nuclear, and cortical opacities (defined as a grade > or = 2 in either eye), as well as prevalence of any lens changes (including history of previous cataract surgery and/or cataract too advanced to grade). RESULTS: Overall, 41% of the Barbados Eye Study population had any lens changes, including 3% with aphakia or an intraocular lens. Among the population of African descent, cortical opacities (34%) were most prevalent, followed by nuclear (19%) and posterior subcapsular (4%) opacities. Prevalence of all opacity types increased with age (P < .001). Cortical and nuclear opacities were more frequent in women than men. When prevalence of a single kind of opacity was considered, 21% of participants had cortical only, 6% had nuclear only, and 0.4% had posterior subcapsular only; 13% had mixed opacities. Visual acuity loss to worse than 20/40 in the more affected eye was present in 48%, 26%, and 18% of nuclear only, posterior subcapsular only, and cortical only types, respectively, and in 53% of mixed opacities. CONCLUSIONS: The Barbados Eye Study provides the first prevalence data on different types of lens opacities in a large, predominantly black population. Whereas nuclear opacities are most common in white populations, cortical opacities were the most frequent type in the Barbados Eye Study, a finding of possible etiologic relevance. Other results highlight a higher frequency of opacities in women than men and a high prevalence of visual acuity loss in affected eyes.

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PubMed1997

Distribution of intraocular pressure. The Barbados Eye Study.

OBJECTIVE: To provide data on the distribution of intraocular pressure (IOP) in a predominantly black population, which has a high prevalence of open-angle glaucoma. DESIGN: Population-based prevalence study. SETTING AND PARTICIPANTS: Participants (N = 4601) (age range, 40-84 years) who had undergone applanation tonometry measurements in the Barbados Eye Study. Self-reported race was 93% black, 4% mixed (black and white), and 3% white or other. DATA COLLECTION: A standardized protocol included applanation tonometry and other ocular measurements, fundus photography, demographic data, and an interview. MAIN OUTCOME MEASURES: The average of 3 IOP measurements at the Barbados Eye Study visit was used to compare IOP by self-reported race. Descriptive data on IOP by age, sex, glaucoma status, and cup-disc ratio were examined in the black population. RESULTS: The IOP was highest in the population of African origin. The mean (+/-SD) IOP values for black, mixed, and white participants were 18.7 +/- 5.2, 18.2 +/- 3.8, and 16.5 +/- 3.0 mm Hg, respectively. An IOP greater than 21 mm Hg was present in 18.4%, 13.6%, and 4.6% of the black, mixed, and white participants, respectively. In analyses that were adjusted for age, sex, and glaucoma status, such values were 5 times as likely in black than white participants and 3.5 times as likely in mixed race participants (P < .01). Among the black participants, the mean IOP increased approximately 1 mm Hg for every increase in 10 years of age. After excluding persons with any type of glaucoma, suspected glaucoma, or a history of glaucoma treatment, women had significantly (P < .01) higher IOP values; however, no significant IOP trends by sex were evident in the group with glaucoma. The IOP was also positively associated (P < .05) with vertical cup-disc ratios. After 2 visits, the IOP remained 21 mm Hg or less in 21% of the persons with glaucoma vs 64% of those without glaucoma. CONCLUSIONS: In the black participants, the IOP was higher than in the white participants. The IOP was also associated with age and cup-disc ratios. The results showed that open-angle glaucoma and a high IOP alone have a different distribution by sex; although open-angle glaucoma was more frequent in men, ocular hypertension was more frequent in women. These data have implications for the detection and causation of open-angle glaucoma in this high-risk population.

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PubMed1997

Lens opacities, demographic factors and nutritional supplements in the Barbados Eye Study.

BACKGROUND: This study evaluated the association of age-related lens opacities with the use of nutritional supplements and demographic factors among 4314 black participants (> or = 40 years) in the population-based Barbados Eye Study. METHODS: Lenses were classified at the slit lamp by the Lens Opacities Classification System II (LOCS II); a score > or = 2 was used to define the presence of gradable lens opacities, by type. Lens changes also included prior cataract surgery or cataract too advanced to grade. Associations with risk factors were evaluated by logistic regression analyses. RESULTS: The study identified 1800 individuals with lens changes in at least one eye; 229 had nuclear opacities only; 851 had cortical opacities only. Older age and indicators of lower socioeconomic status (low education and/or non-professional occupation), were positively associated with both nuclear (odds ratio [OR] = 1.90) and cortical (OR = 1.47) opacities. Women had an increased risk of cortical opacities (OR = 1.41). Regular users of nutritional supplements were less likely to have lens changes (OR = 0.78) and, specifically, cortical opacities (OR = 0.77). The association with nutritional supplements was present in those < 70 years, but not at older ages. CONCLUSIONS: The study supports the association of lower socioeconomic status with lens changes, including nuclear and cortical lens opacities. The findings also suggest that regular users of nutritional supplements have a one-fourth lower risk of lens changes and particularly, of cortical opacities; a result seen at ages under 70 years. The associations with potentially modifiable factors indicate the need for further evaluations, given the high prevalence of lens opacities.

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PubMed1995

Features of age-related macular degeneration in a black population. The Barbados Eye Study Group.

OBJECTIVE: To report on the frequency of features of age-related macular degeneration in a black population based on fundus photograph gradings. DESIGN: Population-based study. SETTING: Barbados, West Indies. STUDY POPULATION: Residents of Barbados, selected by a random sample of Barbados-born citizens, aged 40 to 84 years. MAIN OUTCOME MEASURE: Gradings from 30 degrees stereoscopic macular photographs. RESULTS: Black participants (n = 3444) completed examinations at the study site and had gradable macular photographs in both eyes. Drusen larger than 63 microns occurred with comparable frequency in men and women. The frequency of small drusen decreased with age, while medium and large drusen were more common in older participants. Frequencies of all age-related macular degeneration-related characteristics were similar for men and women except for small drusen, which occurred more commonly in women. Confluent drusen and pigment atrophy also increased significantly with age. Exudative features occurred in 0.5% of the participants. CONCLUSIONS: This study provides population-based data on the frequency of features of age-related macular degeneration based on photographic gradings of a black population. Features of early age-related macular degeneration were common, but appeared at a lower frequency than has been reported for white populations. Exudative disease was infrequent, occurring in about one of 200 participants.

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PubMed1995

Risk factors for open-angle glaucoma. The Barbados Eye Study.

OBJECTIVE: To evaluate risk factors for open-angle glaucoma among black participants in the Barbados Eye Study. DESIGN: Population-based study of demographic, medical, ocular, familial, and other factors possibly related to open-angle glaucoma. SETTING AND PARTICIPANTS: The Barbados Eye Study included 4709 Barbados residents identified by a simple random sample of Barbadian-born citizens, 40 to 84 years of age; participation was 84%. This report is based on the 4314 black participants examined at the study site; 302 (7%) met the Barbados Eye Study criteria for open-angle glaucoma. DATA COLLECTION: A standardized protocol included applanation tonometry, Humphrey perimetry, fundus photography, blood pressure, anthropometry, and an interview. An ophthalmologic examination was performed for participants who met specific criteria. MAIN OUTCOME MEASURES: Open-angle glaucoma was defined by the presence of both characteristic visual field defects and optic disc damage. Association of open-angle glaucoma with specific factors was evaluated in logistic regression analyses. RESULTS: Age, male gender, high intraocular pressure, and family history of open-angle glaucoma were major risk factors; the latter association was stronger in men than women. Lean body mass and cataract history were the only other factors related to open-angle glaucoma. Although hypertension and diabetes were common in Barbados Eye Study participants, they were unrelated to the prevalence of open-angle glaucoma. However, associations were found with low diastolic blood pressure-intraocular pressure differences and low systolic and diastolic blood pressure/intraocular pressure ratios. CONCLUSIONS: In the Barbados Eye Study black population, persons most likely to have open-angle glaucoma were older men and had a family history of open-angle glaucoma, high intraocular pressure, lean body mass, and cataract history. These results suggest the importance of possible genetic or familial factors in open-angle glaucoma. The role of vascular risk factors is consistent with our finding of low blood pressure to intraocular pressure relationships, but the results could be explained by the high intraocular pressure in open-angle glaucoma.

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PubMed1994

The Barbados Eye Study. Prevalence of open angle glaucoma.

OBJECTIVE: To describe the design of the Barbados Eye Study and report on the prevalence of open angle glaucoma (OAG) in a predominantly black study population. DESIGN: Population-based prevalence study. SETTING AND PARTICIPANTS: Residents of Barbados, West Indies, identified from a simple random sample of Barbadian-born citizens 40 through 84 years old. DATA COLLECTION: Participants had a comprehensive study visit that included automated perimetry, applanation tonometry, and fundus photography; persons with specific examination findings, as well as a 10% sample of participants, were referred for an ophthalmologic examination and additional tests. OUTCOME: A diagnosis of OAG required both visual field and optic disc criteria for glaucoma damage after excluding other causes. RESULTS: The 4709 participants (83.5% of those eligible) had demographic characteristics that were similar to the census population. Of the 4631 participants who were tested at the study site, 95% completed Humphrey automated perimetry and 97% had photographic or clinical disc gradings; 93% of those referred completed the ophthalmologic examination. In this adult population, the prevalence of OAG by self-reported race was 7.0% (302/4314) in black, 3.3% (6/184) in mixed-race, and 0.8% (1/133) in white or other participants. In black and mixed-race participants, the prevalence reached 12% at age 60 years and older and was higher in men (8.3%) than in women (5.7%), with an age-adjusted male-female ratio of 1.4. In addition, over 3% of the participants were classified as having suspect OAG. CONCLUSIONS: To our knowledge, the Barbados Eye Study is the largest glaucoma study ever conducted in a black population and identified more people with OAG than did any previous population study. The prevalence of OAG was high, especially at older ages and in men. Among participants 50 years old or older, one in 11 had OAG, and prevalence increased to one in six at age 70 years or older. The results highlight the public health importance of OAG in the Afro-Caribbean region and have implications for other populations.

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PubMed1993

Comparison of diabetic retinopathy detection by clinical examinations and photograph gradings. Barbados (West Indies) Eye Study Group.

OBJECTIVE: To compare the use of clinical examination and fundus photograph gradings in detecting diabetic retinopathy in a population that includes persons with and without diabetes. DESIGN: Population-based epidemiologic study. SETTING: Sir Winston Scott Polyclinic, Bridgetown, Barbados, West Indies. PARTICIPANTS: Subset of a random sample of the country's population aged 40 to 86 years. RESULTS: Among 1168 black persons with fundus photograph evaluations, ophthalmologic examinations, diabetes history, and glycated hemoglobin data, 21% reported a history of diabetes; 9.5% had definite diabetes (glycated hemoglobin > 11.5%); and 13.3% had a diabetes history and glycated hemoglobin value less than or equal to 11.5%. The frequency of diabetic retinopathy in this group was 7.7% (90/1168) by clinical examination, 8.7% (102/1168) by photograph gradings, and 6.7% (78/1168) by both methods. CONCLUSIONS: These results suggest that in certain populations that include diabetics and nondiabetics, a clinical examination by an ophthalmologist will detect most cases of diabetic retinopathy identified by disc and macula photographs read by skilled graders. However, it will lead to an underestimate of prevalence. Staff availability and cost, issues not examined in this study, should determine which approach is selected.

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PubMed1989

A pilot project of glaucoma in Barbados.

The prevalence of open-angle glaucoma is believed to be very high among West Indian blacks. To begin investigating the prevalence and risk factors for glaucoma and other eye diseases in Barbados, WI, a pilot study was conducted. The pilot project identified a stratified, random national sample of 300 persons over 35 years of age who were invited to participate in an ophthalmic examination and an interview. Of those contacted 89% were eligible and 95% of these agreed to participate. The overall glaucoma prevalence in the participants was 6%; it was 13% among black and mixed persons over 54 years. Age related cataract, hypertension, and diabetes were frequent findings. Although the sample size of the pilot project is small, the results suggest a high prevalence of glaucoma in Barbados, a finding that merits further study.

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PubMed1988

Design of a pilot study of glaucoma in Barbados.

In Barbados, West Indies, open-angle glaucoma is a major cause of blindness, presenting early and with advanced visual loss. This report describes the design of a pilot project that evaluated the feasibility of an epidemiologic study to measure glaucoma prevalence and ascertain risk factors in this population. A major goal of the pilot project was to test the proposed sampling and recruitment methods for the larger study. The pilot project identified a random national sample of 300 persons ≥ 35 years, 100 from each of three geographic strata, who were invited to participate in a comprehensive interview and ophthalmologic examination. Because the pilot study was still ongoing at the time of this report, data are available only on the first 172 persons in the sample; 88 percent of those contacted were eligible for the study and 97 percent agreed to participate without any differential participation by geographic area. Preliminary data on the first 170 persons examined show that 20 to 25 percent of participants had best corrected visual acuity of 20/40 or worse; about 10 percent had intraocular pressure >21 mmHg; over 20 percent had cup-disc ratios of ≥0.5; and ten persons had open-angle glaucoma.

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PubMed1988

Eye health.

The status of eye care in the Caribbean is discussed. Methods of primary eye care providers at all levels from primary to tertiary in the region are presented against a background of the major causes of blindness, cataract, glaucoma, and diabetic retinopathy. Epidemiological surveys examining prevalence, risk factors, and intervention programs are being undertaken.

Eye Diseases↗
PubMed1983

Indigent care limitation in university-owned hospitals.

In recent years the ability of teaching hospitals to finance the expenses associated with the provision of medical care to the indigent has come increasingly into question. Such concerns develop because of the burden cost shifting places on other patients and the potentially adverse market position resulting for the hospital. The University of Nebraska's experience in care for the indigent has been an economic success. The social, political, educational and ethical aspects of policies in this area, however, have not yet permitted definitive assessment.

Costs and Cost Analysis↗