Excess Hospitalizations, Hospital Days, and Inpatient Costs Among People With Diabetes in Andalusia, Spain

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1 Epidemiology/Health Services/Psychosocial Research O R I G I N A L A R T I C L E Excess Hospitalizations, Hospital Days, and Inpatient Costs Among People With Diabetes in Andalusia, Spain GABRIEL OLVEIRA-FUSTER, MD 1 PILAR OLVERA-MÁRQUEZ, MD 1 FLORENTINO CARRAL-SANLAUREANO, MD 2 1 STELLA GONZÁLEZ-ROMERO, MD MANUEL AGUILAR-DIOSDADO, MD 2 FEDERICO SORIGUER-ESCOFET, MD 1 OBJECTIVE The goal of this study was to estimate the excess hospitalizations, hospital days, and inpatient costs attributable to diabetes in Andalusia, Spain (37 hospitals, 7,236,459 inhabitants), during 1999 compared with those without diabetes. RESEARCH DESIGN AND METHODS This study was an analysis of all hospital discharges. Those with an ICD-9-CM code of 250 as either the main or secondary diagnosis were considered to have been admissions of individuals with diabetes. An estimate of costs was applied to each inpatient admission by assigning a cost weight based on the diagnostic-related group (DRG) related to each admission. RESULTS A total of 538,580 admissions generated 4,310,654 hospital bed-days and total costs of 940,026,949. People with diabetes accounted for 9.7% of all hospital discharges, 13.8% of total stays, and 14.1% of the total cost. Of the total cost for individuals with diabetes ( 132,509,217), 58.3% were excess costs, of which 47% was attributable to cardiovascular complications and 43% to admissions for comorbid diseases. Individuals years of age accounted for 75% of the excess costs. The rate of admissions during the study year was 145 per 1,000 inhabitants for individuals with diabetes compared with 70 admissions per 1,000 inhabitants for individuals without diabetes. CONCLUSIONS The costs arising from hospitalization of individuals with diabetes are disproportionate in relation to their prevalence. For those aged 45 years, cardiovascular complications were clearly the most important factor determining increased costs from diabetes. Diabetes is one of the most important public health problems worldwide. An estimated 300 million individuals will have the disease by the year 2025 (1). Prevalence studies in Spain corroborate this trend (2). Studies of the costs associated with diabetes show that the direct burden resulting from its treatment is very high in relation to its prevalence (3 8). From 30 to 50% of expenses arising Diabetes Care 27: , 2004 from diabetes correspond to indirect costs, with the rest corresponding to the direct cost of health care (3,6,9). Studies in Spain, Europe, and the U.S. generally agree that most direct costs are due to inpatient care of the associated chronic complications of diabetes (3 9). Care of individuals with diabetes generates a disproportionate use of hospital resources relative to the prevalence of diabetes (10 12). The greatest impact on From the 1 Endocrinology and Nutrition Service, Carlos Haya Universitary Hospital, Malaga, Spain; and the 2 Endocrinology and Nutrition Service, Puerta del Mar Universitary Hospital, Cadiz, Spain. Address correspondence and reprint requests to Gabriel Olveira-Fuster Unidad de Nutrición, 4 a planta, Pabellón A Hospital Carlos Haya Avenida Carlos Haya s/n, Malaga 29010, Spain. gabrielm. olveira.sspa@juntadeandalucia.es. Received for publication 2 December 2003 and accepted in revised form 5 May Abbreviations: DRG, diagnostic-related group. A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances by the American Diabetes Association. hospital stay and expense is from hospitalizations for chronic complications, especially cardiovascular complications (8,12). Data published in Spain on hospital costs generally came from small- or medium-sized hospitals (10 12), or they were calculated from theoretical estimates based on prevalence studies (7) or from smaller samples of patients from the primary care setting only (4,8). Very few European studies, and none in Spain, have focused their hospitalization data of individuals with diabetes to estimate the excess cost. Moreover, those that have have carried out population-based analyses using low populational prevalence data for diabetes (13). In this study, we estimated the excess costs attributable to hospitalization of individuals with diabetes using a population-based analysis in Andalusia, a region in Southern Spain with 7 million inhabitants, using up-to-date prevalence data for diabetes. RESEARCH DESIGN AND METHODS Andalusia has its own health care service under the Andalusian Consejería de Salud. The population of Andalusia is 7,236,459 inhabitants, with health care provided to 98% of these individuals (14). We analyzed all admissions during 1999 to all the hospitals under the jurisdiction of the Consejería de Salud (5 first-level regional centers, 9 second level, and 18 local). The only admissions excluded were those of newborns. The study population was stratified by age into the following groups: 15 years, years, years, and 75 years. The diagnoses and procedures of all hospital discharges were coded in accordance with the ICD-9-CM. All hospital discharges that included diagnostic category 250 as the main or secondary medical diagnosis (in any of its 10 sections) were considered to refer to individuals with diabetes. The remaining hospital discharges not classified under diagnostic category 250 were considered to relate to treatment of individuals without diabetes DIABETES CARE, VOLUME 27, NUMBER 8, AUGUST 2004

2 Olveira-Fuster and Associates Table 1 Groups of hospital discharges based on DRG DRGs Acute complications 294, 295 Chronic complications Neurological 007, 008, , 045, 034, 035, 045, 531, 533 Ophthalmological 036, 037, 039, 042, 046, 047, 534, 535 Cardiovascular 014, 015, , , 127, 128, , , 285, 478, 479, 796, 797, 532, 543, 544, 549, 550, 808 Musculoskeletal and skin , 244, 245, , 563, 564 Genitourinary 302, 316, 317, 325, 326, 331, 332, 341, 568, 569 Comorbidity All remaining hospitalizations Estimation of costs A specific financial control system has been established by the Consejería de Salud based on the DRG of the patient. An estimate of costs was applied to every inpatient admission by assigning a cost weight based on the DRG related to each admission. In 1999, the cost of one DRG point was 1,357. The sum of all such cost weights was calculated for each agegroup and disease type according to the DRG for both diabetes- and non diabetes-related admissions. The results are expressed in euros. All hospitalization episodes were classified according to the diagnosticrelated group (DRG) derived from the corresponding ICD-9-CM codes and translated by the All Patients DRGs software (vol. 12, 1996). Each diabetic subject was further classified into the following mutually exclusive groups based upon reported DRG (Table 1): 1) acute complications, 2) chronic complications of diabetes, and 3) other comorbid conditions (all remaining hospitalizations). The specific conditions considered to be chronic complications of diabetes and the associated DRGs were based on those published by the American Diabetes Association and in other relevant peerreviewed literature (6,10,15) (Table 1). Rates of hospitalization for individuals with and without diabetes were calculated for each age-group by dividing the number of hospitalizations by the respective population at risk. The relative risk of hospitalization was estimated by dividing the rate of hospitalization of individuals with diabetes by the rate of hospitalization of individuals without diabetes. We used the prevalence data of diabetes in the general population published for the different populations in Spain (2,16). The following prevalence data were used: 15 years of age (0.1% of the general population), years (0.85% of the general population), years (7% of the general population), and 75 years (17% of the general population). Determination of excess hospitalization, stays, and costs The excess numbers of admissions, hospital days, and costs generated by individuals with diabetes were calculated by estimating the expected value, based on admission indexes, the mean stay, and the hospital costs in individuals without diabetes for each group studied. These were then subtracted from the observed findings for individuals with diabetes (13). These calculations were made for the total number of admissions and for each of the different groups studied classified according to the DRG and age. RESULTS Table 2 summarizes the overall and age-grouped results of the de- Table 2 Demographic characteristics, hospital care resources, and costs in individuals hospitalized with and without diabetes Individuals with diabetes Individuals without diabetes Total admissions among the different age-groups* 52,454 (9.7) 486,126 (90.3) 15 years 615 (1) 59,459 (99) years 2,793 (1.3) 204,483 (98.7) years 33,428 (16.5) 169,447 (83.5) 75 years 15,618 (22.9) 52,737 (77.2) Sex Men 25,241 (44.3) 215,538 (48.1) Women 27,213 (55.7) 270,589 (51.9) Total bed-days* 596,851 (13.8) 3,713,803 (86.2) Mean length of stay among the different age-groups (days) years years years years Total inpatient cost among the different age-groups* 132,509,217 (14.1) 807,517,732 (85.9) 15 years 723,055 (1) 68,862,789 (99) years 4,885,394 (1.9) 248,984,696 (98.1) years 85,421,739 (19) 364,297,480 (81) 75 years 41,479,029 (24.9) 125,372,767 (75.1) Data are n (%). *Percent compared with the total number of inpatients in each age-group. Percent compared with the total number of patients in each group (diabetes and no diabetes). DIABETES CARE, VOLUME 27, NUMBER 8, AUGUST

3 Excess inpatient costs for diabetes Figure 1 Proportion corresponding to the excess cost compared with the total cost generated by hospitalization of individuals with diabetes (total and by age-group). mographic data for admissions, stays, and costs generated. Of the 538,580 admissions, 52,454 corresponded to individuals with diabetes. The total number of admissions generated 4,310,654 beddays (596,851 for individuals with diabetes) and total costs of 940,026,949 ( 132,509,217 for individuals with diabetes). The mean cost per admission was 2,526 for individuals with diabetes and 1,661 for individuals without diabetes. Of the total cost generated by hospitalization of individuals with diabetes ( 132,509,217), 58.3% ( 77,206,772) was directly attributable to the presence of diabetes (excess costs). Figure 1 specifies the percentages attributable to the excess costs in relation to the total cost generated by hospitalization of individuals with diabetes. Figure 2 shows the percentage contribution by age-group to the excess costs generated by hospitalization of individuals with diabetes. Table 3 details, for the total group and for each of the age-groups studied, the distribution of admissions, stays, and costs of the individuals with diabetes as well as the expected and the excess costs for each of the diagnostic subgroups studied. The main determinant factors in the 132,509,217 generated by hospitalization of individuals with diabetes were admissions for cardiovascular complications ( 46,083,642 [34.8% of the total], of which 36,304,002 [27.4% of the total] were directly attributable to diabetes) and diabetes comorbid conditions ( 74,931,013 [56.5% of the total], of which 33,240,356 [25.1% of the total] were directly attributable to diabetes). The rate of admissions during the study year was 145 per 1,000 inhabitants for individuals with diabetes compared with 70 admissions per 1,000 inhabitants for individuals without diabetes. The rates of admission per age-group for individuals with diabetes versus individuals without diabetes were 468 vs. 45 admissions per 1,000 inhabitants ( 15 years of age), 95 vs. 59 admissions per 1,000 inhabitants (15 44 years of age), 230 vs. 88 admissions per 1,000 inhabitants (45 75 years of age), and 234 vs. 161 admissions per 1,000 inhabitants ( 75 years of age). CONCLUSIONS This study shows that individuals with diabetes have a high risk of hospital admission compared with individuals without diabetes. There was a notable increase in all age-groups in stays and a disproportionate cost associated with the diagnosis. Almost 60% of all hospital costs for hospitalization of people with diabetes were excess costs, either due to chronic or acute diseases related with complications, especially those related with the cardiovascular system, or to the increased expense associated with admission for other comorbid diseases not related with diabetes. In absolute terms, it was the age-group of 45- to 75-year-old individuals who contributed most (75%) to the excess costs (Fig. 2). The rates of hospitalization for individuals with diabetes were clearly above those of individuals without diabetes in all age-groups; this is in agreement with other studies (6,10,15). The reasons for the excess admissions (and subsequent costs) in the various age-groups were well differentiated (Table 3). In individuals 45 years of age, this was mainly due to hospitalizations for decompensation of their diabetes. In the other two agegroups ( 45 years), cardiovascular complications were the most important diabetes-related factors determining increased costs. In absolute terms, the main factor contributing to the excess costs generated by diabetes was related to admissions for cardiovascular complications (almost 50% of the estimated excess). This occurred in all age-groups, although it was especially marked in individuals from years of age, the data being similar to those reported by us and others (4,6,12,13,17). The fact that our findings are similar to data from other countries, both European and American, with different health care systems reinforces the validity of the data and emphasizes the universal role of diabetes in increasing health care costs. Two factors explain this. First, the risk of admission due to cardiovascular disease in individuals with dia- Figure 2 Percentage contribution according to age of the excess costs generated by hospitalization of individuals with diabetes DIABETES CARE, VOLUME 27, NUMBER 8, AUGUST 2004

4 Olveira-Fuster and Associates Table 3 Distribution of hospital admissions, hospital days, and costs for individuals with diabetes compared with the expected values for the total number of patients by age-group Hospital admissions Hospital days Costs (euros) Actual Expected Excess Percent excess Relative risk* Actual Expected Excess Percent excess Actual Expected Excess Percent excess All age-groups Acute complications 2,557 2, ,333 22, ,252,095 3,252, Neurological ,572 4,562 9, ,520,710 1,285,427 2,235, Ophthalmological 1, ,180 2,959 2, ,652,065 1,097, , Cardiovascular 17,174 4,114 13, ,650 40, , ,083,642 9,779,640 36,304, Musculoskeletal and skin ,482 2,661 2, , , , Genitourinary ,808 3,359 6, ,200, ,808 1,381, Comorbidity 29,122 19,220 9, , , , ,931,013 41,690,657 33,240, Total 52,454 25,369 27, , , , ,509,217 55,302,444 77,206, Individuals 75 years of age Acute complications ,130 5, , , Neurological ,245 2,517 2, ,367, , , Ophthalmological ,101 1, , , ,835 Cardiovascular 5,300 2,182 3, ,057 21,904 37, ,175,988 5,497,688 9,678, Musculoskeletal and skin ,495 1, , ,682 27, Genitourinary ,508 1,834 1, , , , Comorbidity 8,816 7,680 1, ,002 98,846 8, ,030,973 18,330,398 4,700, Total 15,618 10,802 4, , ,567 54, ,479,029 25,678,759 15,800, Individuals years of age Acute complications ,838 8, ,163,354 1,163, Neurological ,913 1,934 5, ,057, ,342 1,501, Ophthalmological ,719 1,502 2, ,178, , , Cardiovascular 11,643 1,899 9, ,187 17, , ,348,995 4,218,306 26,130, Musculoskeletal and skin ,835 1,500 2, , , , Genitourinary ,809 1,461 4, ,364, , , Comorbidity 18,479 9,810 8, , , , ,707,862 21,318,638 27,389, Total 33,428 12,754 20, , , , ,421,739 27,420,240 58,001, Individuals years of age Acute complications ,037 5, , , Neurological ,158 23,333 70, Ophthalmological ,136 10,996 61, Cardiovascular , , ,278 61, , Musculoskeletal and skin ,263 31, Genitourinary ,229 28,163 27, Comorbidity 1,689 1, ,209 9,202 5, ,026,573 1,979,162 1,047, Total 2,793 1,753 1, ,022 9,741 13, ,885,394 2,134,513 2,750, Individuals 15 years of age Acute complications ,328 3, , , Chronic complications ,857 6,473 9, Comorbidity ,605 62, , Total , , ,055 68, , *Relative risk of admission for individuals with diabetes compared with individuals without diabetes for each age-group and disease type. DIABETES CARE, VOLUME 27, NUMBER 8, AUGUST

5 Excess inpatient costs for diabetes betes is clearly greater in all age-groups studied; our data are similar to or even higher than those of others (13,17,18). Second, admissions of individuals with diabetes due to cardiovascular disease are more complex and prolonged than admissions of individuals without diabetes (from 1 to 3.4 days longer, depending on the age-group), thereby generating greater consumption of resources. Patients who have macrovascular complications cause a notable increase (at least twofold) in the direct annual costs resulting from their care, with greater increases among the younger patients (4,19,20). Individuals with diabetes who are 50 years old and who also have the metabolic syndrome, i.e., almost 90% of this group, are those who most often have cardiovascular disease, whereas this disease is hardly present in individuals with diabetes but without the metabolic syndrome (21). In our study, it was not possible to determine the main cause of the increase in admissions for cardiovascular disease or its associated costs (whether they were due to diabetes itself or to the associated disease). Nevertheless, it seems clear that reducing the costs associated with diabetes requires aggressive control of the other components of the metabolic syndrome (obesity, blood pressure, or dyslipidemia) as well as intensifying the treatment of diabetes. This should result in notable long-term savings in both monetary terms and possibly also in terms of improved quality of life, although it probably means greater short-term expenses (5,8,22). A more aggressive treatment of diabetes in hospitalized patients (especially those admitted for cardiovascular disease) with the aim of achieving optimum metabolic control is also effective at reducing morbidity and mortality and, consequently, the associated expenses (23). Patients with diabetes have a clear increase in the number of hospitalizations, the number of hospital days, and the costs associated with admission for comorbid diseases not related with diabetes. This had important economic repercussions in all the age-groups, as it accounted for 43% of the excess costs. The presence of diabetes may increase the incidence and severity of other diseases, leading to hospitalization, a longer mean stay, and more hospital complications. The increase in the number of visits to health care centers by individuals with diabetes also results in more admissions. For certain diseases, therefore, the presence of diabetes tends to increase the likelihood of hospital admission or of receiving more aggressive therapy (10,15). Our study, however, is not without limitations. First, our estimation of costs largely depended on prevalence figures for diabetes. Nevertheless, we decided to use age values similar to other recent studies in our area (2,16). These figures are much higher than those used by others (7,13) but are probably nearer the actual figures. Lower figures would have resulted in possibly even higher figures for excess costs. Second, the system of cost assignment was based on DRGs that were not designed for individuals with diabetes (who have longer mean stays than individuals without diabetes) and which simplify primary and secondary diagnoses (with the corresponding loss of information in older individuals with diabetes, who usually have more comorbid diseases). Third, it has been shown, both in our area (24) and in other countries (25), that undercoding of hospital diabetes can be very high (from 20 to 61% of all individuals with diabetes), which would result in underestimation of the costs (24,26). In conclusion, our study demonstrated that almost 60% of costs generated by hospitalization of individuals with diabetes (in a large sample of hospitals from southern Spain) are specifically attributable to the disease itself. Hospitalizations for cardiovascular complications and increased costs associated with hospitalization of individuals with diabetes for other unrelated diseases were notable. The optimal management of blood glucose, blood pressure, and lipid concentrations and the early detection and management of existing complications should possibly result in an important reduction of the excess costs associated with hospitalization of individuals with diabetes. For those individuals age 45 years, cardiovascular complications were clearly the most important factor determining increased costs from diabetes. Acknowledgments This study was partly financed by a grant from the Consejería de Salud de la Junta de Andalucía (01/118) and by a grant from the Instituto de Salud Carlos III, RCMN (C03/08), Spain. The authors thank Ian Johnstone for the English language version of the study. References 1. King H, Aubert RE, Herman WH: Global burden of diabetes, : prevalence, numerical estimates, and projections. Diabetes Care 21: , Goday A, Delgado A, Díaz-Cadorniga F, de Pablos P, Vazquez JA, Soto E: Epidemiología de la diabetes tipo 2 en España. Endocrinol Nutr 49: , Rubin RJ, Altman WM, Mendelson DN: Health care expenditures for people with diabetes mellitus, J Clin Endocrinol Metab 78:809A 809F, Jonsson B: Revealing the cost of type II diabetes in Europe. Diabetologia 45:S5 12, Olveira G, Carral F: Costes de la diabetes: una reflexión desde la situación asistencial en España. Av Diabetol 16: , American Diabetes Association: Economic cost of diabetes in the U.S. in Diabetes Care 26: , Hart WM, Espinosa C, Rovira J: El coste de la diabetes mellitus conocida en España. Med Clin (Barc) 109: , Mata M, Antonanzas F, Tafalla M, Sanz P: The cost of type 2 diabetes in Spain: the CODE-2 study. Gac Sanit 16: , Lopez-Bastida J, Serrano-Aguilar P, Duque-Gonzalez B: The social and economic cost of diabetes mellitus. Aten Primaria 29: , Carral F, Olveira G, Salas J, García L, Sillero A, Aguilar M: Care resource utilization and direct costs incurred by people with diabetes in a Spanish hospital. Diabetes Res Clin Pract 56:27 34, Monereo S, Pavon I, Vega B, Elviro R, Duran M: Complicaciones de la diabetes mellitus: impacto sobre los costes hospitalarios. Endocrinologia 46:55 59, Carral F, Aguilar M, Olveira G, Mangas A, Domenech I, Torres I: Increased hospital expenditures in diabetic patients hospitalized for cardiovascular diseases. 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6 Olveira-Fuster and Associates tinez G, Ruiz de Adana S, Catala M, Merelo MJ, Aguilar M, Tinahones F, Garcia-Almeida JM, Gomez-Zumaquero JM, Cuesta-Munoz AL, Ortego J, Freire JM: Prevalence of latent autoimmune diabetes of adults (LADA) in Southern Spain. Diabetes Res Clin Pract 56: , Glauber H, Brown J: Impact of cardiovascular disease on health care utilization in a defined diabetic population. J Clin Epidemiol 47: , Massi-Benedetti M: The cost of diabetes type II in Europe: the CODE-2 Study. Diabetologia 45:S1 S4, Nichols GA, Brown JB: The impact of cardiovascular disease on medical care costs in subjects with and without type 2 diabetes. Diabetes Care 25: , Brandle M, Zhou H, Smith BRK, Marriot D, Burke R, Tabaei BP, Brown MB, Herman WH: The direct medical cost of type 2 diabetes. Diabetes Care 26: , Alexander CM, Landsman PB, Teutsch SM, Haffner SM: NCEP-defined metabolic syndrome, diabetes, and prevalence of coronary heart disease among NHANES III paricipants age 50 years and older. Diabetes 52: , Klonoff D, Schwartz D: An economic analysis of interventions for diabetes. Diabetes Care 23: , Van Den Berghe G, Mesotten D: Clinical potential of insulin therapy in critically ill patients. Drugs 63: , Carral F, Olveira G, Aguilar M, Ortego J, Gavilán I, Domenech I, Escobar L: Hospital discharge records under-report the prevalence of diabetes in inpatients. Diabetes Res Clin Pract 59: , Leventan CS, Passaro M, Jablonski K, Kass M, Ratner RE: Unrecognized diabetes among hospitalized patients. Diabetes Care 21: , Ragnarson-Tennvall G, Apelqvist J, Eneroth M: The inpatient care of patients with diabetes mellitus and foot ulcers: a validation study of the correspondence between medical records and the Swedish Inpatient Registry with the consequences for cost estimations. J Intern Med 248: , 2000 DIABETES CARE, VOLUME 27, NUMBER 8, AUGUST