Abstract

Introduction

Chronic non-communicable diseases (CNCDs) are an important cause of morbidity and mortality in the world. According to data from the Global Burden of Disease Study, CNCDs accounted for 43% of disability-adjusted life years (DALYs) in 1990, increasing to 54% in 2010 ¹1. Murray CJL, Vos T, Lozano R, Naghavi M, Flaqxman AD, Michaud C, et al. Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380:2197-223.. According to the World Health Organization, the human and socioeconomic impact of CNCDs affects progress with the Millennium Development Goals, and the consequences are felt in the majority of countries, especially in low and middle income countries and in vulnerable populations ²2. World Health Organization. Global status report on noncommunicable diseases 2010. Geneva: World Health Organization; 2011.^,33. World Health Organization. Global status report on noncommunicable diseases 2014. Geneva: World Health Organization; 2014.. In Brazil, the obesity epidemic is considered the leading cause of the increase in prevalence of CNCDs, directly affecting the Millennium Development Goals⁴4. Duncan BB, Chor D, Aquino EML, Bensenor IM, Mill JG, Schmidt MI, et al. Doenças crônicas não transmissíveis no Brasil: prioridade para enfrentamento e investigação. Rev Saúde Pública 2012; 46 Suppl 1:126-34.^,55. Flor LS, Campos MR, Oliveira AF, Schramm JMA. Diabetes burden in Brazil: fraction attributable to overweight, obesity, and excess weight. Rev Saúde Pública 2015; 49:29..

Among the CNCDs, type 2 diabetes mellitus is considered an epidemic and accounts for approximately 90% of total diabetes cases ⁶6. International Diabetes Federation. IDF diabetes atlas. 6th Ed. Brussels: International Diabetes Federation; 2013.. According to estimates for the year 2010, 285 million individuals over 20 years of age were living with diabetes in the world, and by 2030 this figure could reach 439 million ⁷7. Shaw JE, Sicree RA, Zimmet PZ. Global estimates of the prevalence of diabetes for 2010 and 2030. Diabetes Res Clin Pract 2010; 87:4-14.. It is believed that approximately 50% of diabetics are unaware of their disease ⁶6. International Diabetes Federation. IDF diabetes atlas. 6th Ed. Brussels: International Diabetes Federation; 2013..

In Brazil, the most comprehensive study on type 2 diabetes mellitus prevalence was performed in 1988 in nine state capitals and estimated the prevalence at 7.4% of adults 30 to 69 years of age ⁸8. Malerbi DA, Franco LJ; Brazilian Cooperative Group on the Study of Diabetes Prevalence. Multicenter study of the prevalence of diabetes mellitus and impaired glucose tolerance in the urban Brazilian population aged 30-69 yr. Diabetes Care 1992; 15:1509-16.. According to the International Diabetes Federation, Brazil ranked fourth among the world's countries in number of diabetics, with some 11.9 million in 2013 ⁹9. Bertoldi AD, Kanavos P, França GVA, Carraro A, Tejada CA, Hallal PC, et al. Epidemiology, management, complications and costs associated with type 2 diabetes in Brazil: a comprehensive literature review. Global Health 2013; 9:62..

Population aging, growing obesity prevalence, sedentary lifestyle, and urbanization are considered the leading factors in the increase in type 2 diabetes mellitus incidence and prevalence worldwide ³3. World Health Organization. Global status report on noncommunicable diseases 2014. Geneva: World Health Organization; 2014.^,1010. Sociedade Brasileira de Diabetes. Diretrizes da Sociedade Brasileira de Diabetes: 2013-2014. São Paulo: Sociedade Brasileira de Diabetes; 2014.. This scenario is taking a high social and financial toll on patients and the health system, since type 2 diabetes mellitus is also associated with such complications as renal failure, lower limb amputation, blindness, and cardiovascular disease, among others ⁶6. International Diabetes Federation. IDF diabetes atlas. 6th Ed. Brussels: International Diabetes Federation; 2013..

These chronic complications of type 2 diabetes mellitus compromise individuals' functional capacity, autonomy, and quality of life. As for the magnitude of costs with diabetes in Brazil, results show that up to 15.3% of hospital costs in Brazilian Unified National Health System (SUS) from 2008 to 2010 were attributed to diabetes ¹¹11. Rosa R, Nita ME, Rached R, Donato B, Rahal E. Estimated hospitalizations attributable to diabetes mellitus within the public healthcare system in Brazil from 2008 to 2010: study DIAPS 79. AMB Rev Assoc Med Bras 2014; 60:222-30.. As for outpatient treatment costs in the SUS, one study identified annual expenses of USD 2,108 per patient (63.3% direct and 36.7% indirect costs) ¹²12. Bahia LR, Araujo DV, Schaan BD, Dib SA, Negrato CA, Leão MP, et al. The costs of type 2 diabetes mellitus outpatient care in the Brazilian public health system. Value Health 2011; 14(5 Suppl 1):S137-40..

Due to the relevance of type 2 diabetes mellitus as a public health problem in Brazil and worldwide, as well as its chronic complications with varying degrees of severity, the current article presents the findings of the Global Burden of Disease Study in Brazil for the year 2008, with an emphasis on type 2 diabetes mellitus and its complications stratified by gender, age, and region.

Materials and methods

The Global Burden of Disease Study in Brazil was conducted by the Center for Research in Applied Methods for Global Burden of Disease Studies at the Sergio Arouca National School of Public Health, Oswaldo Cruz Foundation (ENSP/Fiocruz) in 2010-2013, using 2008 as the reference year for the data analysis. The study was approved by the Institutional Review Board of ENSP/Fiocruz (CAAE: 0054.0.031.000-11).

The indicator used in burden of disease studies is disability-adjusted life year (DALY), a summary measure aimed at grasping the impact of morbidity and mortality on the population's state of health. DALY thus consists of two components, one that measures years of life lost to premature death (years of life lost - YLLs) and another that measures years of healthy life lost due to health problems or disability (years lived with disability - YLDs) ¹³13. Murray CJL, Lopez AD. Global Burden of Disease and Injury Series. The Global Burden of Disease. A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Boston: Harvard University Press on behalf of the World Health Organization and The World Bank; 1996.. Meanwhile, health problems/chronic complications are subdivided into major analytical groups: I - communicable diseases, maternal/perinatal conditions, and nutritional conditions; II - non-communicable diseases; and III - external causes.

To calculate DALYs, a 3% discount on future benefits was adopted. YLLs were estimated considering deaths from a given disease and life expectancy in Japan according to the reference methodology proposed by Murray & Lopez ¹³13. Murray CJL, Lopez AD. Global Burden of Disease and Injury Series. The Global Burden of Disease. A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Boston: Harvard University Press on behalf of the World Health Organization and The World Bank; 1996.. Mortality data were obtained from the Mortality Information System (SIM) of the SUS, taking the mean value for 2007-2009. Deaths were then selected whose principal cause was coded from E10 to E14 in the International Classification of Diseases, 10^th revision (ICD-10), disaggregated by state, gender, and age bracket. A correction was performed for under-recording of deaths in each state of Brazil, according to gender and age bracket, with a national correction of 28% for individuals under 1 year of age and 13% for individuals over 1 year. According to the traditional Global Burden of Disease Study methodology, deaths from ill-defined causes and cases defined as garbage codes were redistributed proportionally by gender, age bracket, and cause of death in each state of Brazil ¹⁴14. Leite IC, Valente JG, Schramm JMA, Daumas RP, Rodrigues RN, Santos MF, et al. Burden of disease in Brazil and its regions, 2008. Cad Saúde Pública 2015; 31:1551-64..

YLDs were calculated with incident cases, duration of disease, and weight of disabilities taken from the Global Burden of Disease Study in 1990 ¹³13. Murray CJL, Lopez AD. Global Burden of Disease and Injury Series. The Global Burden of Disease. A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Boston: Harvard University Press on behalf of the World Health Organization and The World Bank; 1996.. YLDs were calculated for uncomplicated cases of type 2 diabetes mellitus and the chronic complications considered in Global Burden of Disease Stud: diabetic retinopathy (DR), blindness due to DR (B-DR), diabetic neuropathy (DN), diabetic chronic renal failure (CRF-D), diabetic foot (DF), and amputations. The definitions used in the study were those proposed by Lopez et al. ¹⁵15. Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJL. Global burden of disease and risk factors: disease control priorities project. New York: Oxford University Press; 2006..

After a literature review for definition of clinical and epidemiological parameters on diabetes and related chronic complications, a consensus seminar was held with experts in type 2 diabetes mellitus and its complications, including endocrinologists, ophthalmologists, and clinicians, selected to cover the range of clientele (public and private) and practices in outpatient and hospital care administration, teaching, and research. This selection procedure aimed to avoid biases in selection and measurement of parameters defined by consensus. The expert panel was intended to agree on parameters to be included subsequently in modeling in the DisMod II package (EpiGear, Noosa, Australia; http://www.epigear.com/index_files/dismod_ii.html) ¹⁶16. Barendregt JJ, van Oortmarssen GJ, Vos T, Murray CJ. A generic model for the assessment of disease epidemiology: the computational basis of DisMod II. Popul Health Metr 2003; 1:4. for obtaining the final parameters.

Type 2 diabetes mellitus prevalence was then estimated as the ratio between type 2 diabetes mellitus prevalence obtained in the Multicenter Study on Diabetes Prevalence in 1986-1988 ⁸8. Malerbi DA, Franco LJ; Brazilian Cooperative Group on the Study of Diabetes Prevalence. Multicenter study of the prevalence of diabetes mellitus and impaired glucose tolerance in the urban Brazilian population aged 30-69 yr. Diabetes Care 1992; 15:1509-16. and the population's nutritional status according to the National Survey on Health and Nutrition 1989 ¹⁷17. Coitinho D, Leão M, Recine E, Sichieri R. Condições nutricionais da população brasileira: adultos e idosos. Brasília: Instituto Nacional de Alimentação e Nutrição; 1991. and the Family Budgets Survey 2008-2009 ¹⁸18. Instituto Brasileiro de Geografia e Estatística. Pesquisa de Orçamentos Familiares 2008-2009: antropometria e estado nutricional de crianças, adolescentes e adultos no Brasil. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2010.. DR and DN prevalence rates were agreed on in the expert consensus: 20% of patients with type 2 diabetes mellitus present some type of DR (47.7% mild DR, 19.4% moderate, and 32.9% severe) and 40% some degree of DN. The study by Resnikoff et al. ¹⁹19. Resnikoff S, Pascolini D, Etya'ale D, Kocur I, Pararajasegaram R, Pokharel GP, et al. Global data on visual impairment in the year 2002. Bull World Health Organ 2004; 82:844-51. was used to estimate prevalence of B-DR. Incidence of CRF-D was estimated using data from the Outpatient Information System of the SUS (SIA-SUS), compiling the Authorizations for High-Complexity Procedures (APAC) for the year 2008, in which 25.7% of cases with ICD-10 codes N18 or N19 and 41.8% of cases with type 2 diabetes mellitus and arterial hypertension were attributed to type 2 diabetes mellitus ²⁰20. Sesso RCC, Lopes AA, Thomé FS, Bevilacqua JL, Romão Junior JE, Lugon J. Brazilian dialysis census, 2008. J Bras Nefrol 2008; 30:233-8.. Incidence of amputations was estimated using data from the Hospital Admissions System of the SUS (SIH-SUS) by compiling Authorizations for Hospital Admissions (AIH). The mean for years 2008 to 2010 was used, and 50% of total non-traumatic amputations were attributed to type 2 diabetes mellitus ²¹21. Grupo de Trabalho Internacional sobre Pé Diabético. Consenso internacional sobre pé diabético. Brasília: Secretaria de Estado de Saúde do Distrito Federal; 2001.. This incidence was later corrected, taking as the target the percentage of the population with private health plans in relation to the percentage without such plans, according to data from the Brazilian National Health Agency ²²22. Agência Nacional de Saúde. Beneficiários de planos privados de saúde. http://www.ans.gov.br/perfil-do-setor/dados-e-indicadores-do-setor (acessado em 14/Dez/2012).
http://www.ans.gov.br/perfil-do-setor/da... (correction factor: 1.27 Brazil; 1.10 North and Northeast; 1.50 Southeast; 1.26 South; and 1.16 Central-West). Incidence of diabetic foot was estimated based on the incidence of amputation ²³23. Begg S, Vos T, Barker B, Stevenson C, Stanley L, Lopez AD. The burden of disease and injury in Australia 2003. Canberra: Australian Institute of Health and Welfare; 2007..

The study assumed remission zero for uncomplicated cases of type 2 diabetes mellitus, DR, B-DR, DN, and amputation and 9.5% remission for CRF-D, considering transplant cases registered in 2008 in APAC. The study used relative risk (RR) of mortality from type 2 diabetes mellitus of 2.0 between 30 and 69 years and 1.0 under 29 years and 70 years and older. For DR, B-DR, and DN, we used RR of 1.0 in the age bracket up to 29 years and 2.0 for 30 years and older (parameters agreed on in the expert consensus). RR for amputation was generated by the ratio between mean RR of uncomplicated diabetes mellitus cases ²⁴24. Wild S, Roglic G, Sicree R, Green A, King H. Global burden of diabetes mellitus in the year 2000. Geneva: World Health Organization; 2006. and the RRs reported by Begg et al. ²³23. Begg S, Vos T, Barker B, Stevenson C, Stanley L, Lopez AD. The burden of disease and injury in Australia 2003. Canberra: Australian Institute of Health and Welfare; 2007.. Case-fatality from CRF-D was calculated using the number of deaths recorded in 2008 in APAC.

DisMod II ¹⁶16. Barendregt JJ, van Oortmarssen GJ, Vos T, Murray CJ. A generic model for the assessment of disease epidemiology: the computational basis of DisMod II. Popul Health Metr 2003; 1:4. was used to estimate parameters not available in the literature and to test the internal consistency of the available parameters. After modeling, for individuals up to 29 years of age, the value zero was assigned to incidence rates of uncomplicated cases of type 2 diabetes mellitus and chronic complications. Entry variables in the data modeling were prevalence (type 2 diabetes mellitus, DR, B-DR, and DN) or incidence (CRF-D and amputation) of diseases, remission, mortality (only for t6ype 2 diabetes mellitus), case-fatality (only for CRF-D), and RR (type 2 diabetes mellitus, DR, B-DR, DN, and amputation). Modeling was not necessary for DF, since the incidence was used, estimated from amputations (ratio 1:10) and duration of 2 months for the condition ²³23. Begg S, Vos T, Barker B, Stevenson C, Stanley L, Lopez AD. The burden of disease and injury in Australia 2003. Canberra: Australian Institute of Health and Welfare; 2007..

For uncomplicated cases of type 2 diabetes mellitus, B-DR, DN, DF, amputation, and CRF-D, we used the weights for disabilities reported by Murray & Lopez ¹³13. Murray CJL, Lopez AD. Global Burden of Disease and Injury Series. The Global Burden of Disease. A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Boston: Harvard University Press on behalf of the World Health Organization and The World Bank; 1996.. For type 2 diabetes mellitus, B-DR, DN, and DF, the weights were weighted by the proportion of treatment for each condition (50%, 0%, 40%, 40%, and 0%, respectively), agreed on in the expert consensus. DR used the mean weight reported by Stouthard et al. ²⁵25. Stouthard MEA, Essink-Bot M-L, Bonsel GJ. Disability weights for diseases: a modified protocol and results for a Western European region. Eur J Public Health 2000; 10:24-30. weighted by the prevalence of types of DR.

Table 1 describes the methodology used to obtain the clinical-epidemiological parameters.

Data analysis used the SPSS, version 17.0 (SPSS Inc., Chicago, USA), and estimates were calculated for Brazil and its major geographic regions, stratified by gender and age.

Results

Table 1 shows the incidence rates per 100 thousand inhabitants for type 2 diabetes mellitus cases and chronic complications in men and women in Brazil, after modeling in DisMod II. In general, no relevant differences were found between incidence rates in men and women, with slightly higher rates in men and for amputation and diabetic foot. Chronic complications with the highest incidence were DN and diabetic foot.

Table 2 shows YLLs, YLDs, and DALYs for all non-communicable diseases and injuries (Group II) and specifically for type 2 diabetes mellitus in Brazil and by region. There were 195 DALYs per 1,000 inhabitants in Brazil in 2008. Group II of CNCDs accounted for approximately 77% of the burden of disease that year, ranging from 71.5% in the North to 79.5% in the Southeast. Group II also showed a high share of YLLs and YLDs (65.3% and 89%, respectively).

Type 2 diabetes mellitus accounted for nearly 5% of the burden of disease in Brazil, with 9.2 DALYs per 1,000 inhabitants. Among non-communicable diseases (Group II), the share of type 2 diabetes mellitus was higher: 6.1% in Brazil as a whole (Table 2).

The largest component of the type 2 diabetes mellitus burden was morbidity (53.2%), with 930,478 YLDs. The type 2 diabetes mellitus share of total YLDs for Group II was higher in the South and Southeast, with 7.1% and 6%, respectively, when compared to the national mean of 5.6%. The share of type 2 diabetes mellitus in total YLLs for Brazil was 4.5% (816,716 YLLs), reaching 5.4% in the Northeast. Specifically within Group II, the share of diabetes mellitus increased to 6.9%, with even higher regional rates in the Northeast and North (8.3% and 7%, respectively) (Table 2).

Figure 1 shows the ranking of DALYs from type 2 diabetes mellitus compared to other health problems by age bracket and gender. In all groups starting at 30 years and in both genders, type 2 diabetes mellitus ranked among the five leading health problems in terms of burden of disease in Brazil. Type 2 diabetes mellitus ranked 2^nd in men 59 years or younger, dropping to 5^th starting at 60 years. Among women, type 2 diabetes mellitus ranked 2^nd and 3^rd in the 30-44 and 45-69-year age brackets, respectively, dropping to 4^th in women 70 years or older.

There was a higher proportion of DALYs from type 2 diabetes mellitus in individuals 30 to 59 years of age (59.7%). As for gender, men up to 59 years of age had a slightly higher share of DALYs when compared to women. From 60 years onward there was a higher share in women in the 60-69 and 70 and older age brackets (55.5% and 63.2%, respectively). As for the distribution of YLDs and YLLs in the composition of DALYs from type 2 diabetes mellitus according to age bracket, up to 59 years of age there was a higher proportion of DALYs attributed to morbidity, especially in the 30 to 44-year age bracket, with 86.8% YLDs. From 60 years on there was a reversal of this profile, with a larger share of the mortality component, especially in the 70 and older age bracket, with 82.1% YLLs. That is, age showed an important gradient in the increasing share of mortality from type 2 diabetes mellitus (Figure 2).

As for type 2 diabetes mellitus and its various chronic complications, the burden of morbidity (YLDs) consisted mainly of diabetic retinopathy (42.4%), DN (27.7%) and uncomplicated cases of type 2 diabetes mellitus (20.9%). Regional variation in YLDs showed a concentration in the Southeast. The proportion of YLDs according to regions for type 2 diabetes mellitus as a whole (cases and chronic complications) was 47.3% in the Southeast and 6.1% in the North (Table 3).

Discussion

This study addressed the importance of CNCDs and type 2 diabetes mellitus in Brazil's epidemiological scenario. According to the main findings, type 2 diabetes mellitus showed the most important share among CNCDs, ranking 2^nd in DALYs. The share of YLLs increased with age, especially in Northeast Brazil, while YLDs consisted mostly of chronic complications and were concentrated in the most developed and urbanized regions of Brazil.

The estimated total number of DALYs dropped by approximately 1.5% compared to the GBD Study for Brazil in 1998, consistent with the results of the recent world Global Burden of Disease Study of 2010 ¹1. Murray CJL, Vos T, Lozano R, Naghavi M, Flaqxman AD, Michaud C, et al. Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380:2197-223.. The results were also similar for the share of type 2 diabetes mellitus in total DALYs, which remained around 5% in the last 10 years in Brazil. However, the share of type 2 diabetes mellitus in total DALYs from Group II increased when compared to the share in the Global Burden of Disease Study for Brazil in 1998, from 66.3% to 77.2%.

The share of YLDs in total DALYs from type 2 diabetes mellitus remained higher in the last 10 years when compared to the share of YLLs, which can be explained by the increase in prevalence and maintenance of the mortality rate from type 2 diabetes mellitus in Brazil ⁶6. International Diabetes Federation. IDF diabetes atlas. 6th Ed. Brussels: International Diabetes Federation; 2013.^,2626. Almeida-Pititto B, Dias ML, Moraes ACF, Ferreira SR, Franco DR, Eliaschewitz FG. Type 2 diabetes in Brazil: epidemiology and management. Diabetes Metab Syndr Obes 2015; 8:17-28.. According to Newton et al. ²⁷27. Newton JN, Briggs ADM, Murray CJL, Dicker D, Foreman KJ, Wang H, et al. Changes in health in England, with analysis by English regions and areas of deprivation, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet 2015; 386:2257-74., who analyzed burden of disease in England, there was an important reduction in the burden of mortality due to diabetes, from 1990 (17^th place), to 2005 (27^th place), to 2013 (not ranking among the first 31 places).

Northeast Brazil was the only region in which the type 2 diabetes mellitus profile showed a higher proportion of YLLs than YLDs in DALYs. This may reflect a lower rate of early diagnosis due to difficulties in access to health services as well as barriers to on-going treatment, thereby increasing the share of mortality in type 2 diabetes mellitus. Other relevant aspects include health education issues both with diabetics and health professionals and treatment adherence in a chronic condition like type 2 diabetes mellitus.

Brazil's hinterlands and less economically developed regions have experienced difficulties in implementing the SUS ever since its creation. Since most of these small and/or remote communities have small populations, they suffer from inadequate human and financial resources and infrastructure ²⁸28. Lima APG. Os Consórcios Intermunicipais de Saúde e o Sistema Único de Saúde. Cad Saúde Pública 2000; 16:985-96.. Mendes et al. ²⁹29. Mendes ACG, Miranda GMD, Figueiredo KEG, Duarte PO, Furtado BMASM. Acessibilidade aos serviços básicos de saúde: um caminho ainda a percorrer. Ciênc Saúde Coletiva 2012; 17:2903-12. presented the results of a study in a state capital in Northeast Brazil which revealed great dissatisfaction with the SUS among users and health professionals, due to difficulties with the supply of medicines, tests, and specialized referrals, besides the long waiting time in primary care units.

Type 2 diabetes mellitus in the current study was among the 10 leading causes of DALYs (3^rd in women and 6^th in men), similar to the 8^th place for tropical Latin America estimated in the world Global Burden of Disease Study¹1. Murray CJL, Vos T, Lozano R, Naghavi M, Flaqxman AD, Michaud C, et al. Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380:2197-223.. This illustrates the relevance of type 2 diabetes mellitus in Brazil, especially due to the rising prevalence of risk factors like obesity and sedentary lifestyle ⁵5. Flor LS, Campos MR, Oliveira AF, Schramm JMA. Diabetes burden in Brazil: fraction attributable to overweight, obesity, and excess weight. Rev Saúde Pública 2015; 49:29.^,1818. Instituto Brasileiro de Geografia e Estatística. Pesquisa de Orçamentos Familiares 2008-2009: antropometria e estado nutricional de crianças, adolescentes e adultos no Brasil. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2010.^,3030. Costa JA, Balga RSM, Alfenas RCG, Cotta RMM. Promoção da saúde e diabetes: discutindo a adesão e a motivação de indivíduos diabéticos participantes de programas de saúde. Ciênc Saúde Coletiva 2011; 16:2001-9.. The estimated burden was higher in young populations, reaching 2^nd place in the 30-44-year age group, when compared to the elderly, in whom the burden of cardiac diseases and dementias lead the ranking. The share of YLLs was also higher in DALYs from type 2 diabetes mellitus in the elderly due to this age group's higher mortality rate ¹⁰10. Sociedade Brasileira de Diabetes. Diretrizes da Sociedade Brasileira de Diabetes: 2013-2014. São Paulo: Sociedade Brasileira de Diabetes; 2014..

Uncomplicated cases represented only 20.9% of YLDs from type 2 diabetes mellitus, reflecting Brazil's currently challenging situation with early detection and treatment of cases (which should aim to prevent chronic complications). According to Guidoni et al. ³¹31. Guidoni CM, Oliveira CMX, Freitas O, Pereira LRL. Assistência ao diabetes no Sistema Único de Saúde: análise do modelo atual. Braz J Pharm Sci 2009; 45:37-48., the Family Health Strategy, currently the main primary care mechanism in the SUS, fails to fully meet with the prevention and health promotion recommendations for type 2 diabetes mellitus, thus generating gaps that are ultimately reflected in heavy expenditures on high-complexity expenditures for diabetics. Evaluating the profile of type 2 diabetes mellitus patients hospitalized in the SUS, Artilheiro et al. ³²32. Artilheiro MMVS, Franco SC, Schulz VC, Coelho C. Quem são e como são tratados os pacientes que internam por diabetes mellitus no SUS? Saúde Debate 2014; 38:210-24. showed that the majority reported treatment for systemic arterial hypertension or some comorbidity associated with type 2 diabetes mellitus, such as DN, DR, or peripheral vascular disease. In addition, 24% of these patients had failed to consult a primary care unit in the previous 12 months due to lack of open slots for scheduling appointments, and that 54% had failed to consult an endocrinologist in the previous 3 years due to lack of referral.

Examples of the impact of chronic complications of type 2 diabetes mellitus on patients' health are DR and B-DR, jointly accounting for approximately 45% of all YLDs due to type 2 diabetes mellitus, 9 times the percentage when compared to estimates from the world Global Burden of Disease Study. DR is considered the principal cause of blindness in individuals 20 to 74 years of age, and an estimated 38% of individuals with type 2 diabetes mellitus present some degree of DR at diagnosis ¹⁰10. Sociedade Brasileira de Diabetes. Diretrizes da Sociedade Brasileira de Diabetes: 2013-2014. São Paulo: Sociedade Brasileira de Diabetes; 2014..

According to Rezende et al. ³³33. Rezende KF, Ferraz MB, Malerbi DA, Melo NH, Nunes MP, Pedrosa HC, et al. Predicted annual costs for inpatients with diabetes and foot ulcers in a developing country-a simulation of the current situation in Brazil. Diabet Med 2010; 27:109-12., some 30% of annual cases of DF in Brazil required hospitalization and some 48% of the costs of these admissions related to amputations. There has been a large increase in major amputations, which the same authors attributed to failure in treatment of DF. The situation is even more complicated because diabetic neuropathy is the main cause of ulcers, often detected at first diagnosis of type 2 diabetes mellitus ¹⁰10. Sociedade Brasileira de Diabetes. Diretrizes da Sociedade Brasileira de Diabetes: 2013-2014. São Paulo: Sociedade Brasileira de Diabetes; 2014..

Concerning diabetic chronic renal failure, according to Cherchiglia et al. ³⁴, 20% of patients that began dialysis in the SUS in 2000 presented diabetes as the cause of CRF. Patients were followed for a mean of 4 years, and annual expenditure per patient ranged from approximately BRL 27,000 to BRL 35,000 (USD 8,000-USD 11,000)

Regardless of the type of chronic complication, the greatest obstacles to decreasing their share of total YLDs in type 2 diabetes mellitus relate to effective early diagnosis and efficient treatment of the disease, both of which are still highly precarious in primary care in Brazil. Importantly, since type 2 diabetes mellitus is a difficult disease to manage, prognosis depends largely on lifestyle changes in combination with access to medication, as well as treatment compliance. According to Alfradique et al. ³⁵35. Alfradique ME, Bonolo PF, Dourado I, Lima-Costa MF, Macinko J, Mendonça CS, et al. Internações por condições sensíveis à atenção primária: a construção da lista brasileira como ferramenta para medir o desempenho do sistema de saúde (Projeto ICSAP - Brasil). Cad Saúde Pública 2009; 25:1337-49., type 2 diabetes mellitus is a primary care-sensitive health condition, that is, the hospitalization rates can be decreased by effective measures in primary care. Relatively simple preventive and curative measures can be developed to diagnose and follow individuals with diabetes and consequently avoid chronic complications or delay their progression ¹⁰10. Sociedade Brasileira de Diabetes. Diretrizes da Sociedade Brasileira de Diabetes: 2013-2014. São Paulo: Sociedade Brasileira de Diabetes; 2014.^,3030. Costa JA, Balga RSM, Alfenas RCG, Cotta RMM. Promoção da saúde e diabetes: discutindo a adesão e a motivação de indivíduos diabéticos participantes de programas de saúde. Ciênc Saúde Coletiva 2011; 16:2001-9.^,3232. Artilheiro MMVS, Franco SC, Schulz VC, Coelho C. Quem são e como são tratados os pacientes que internam por diabetes mellitus no SUS? Saúde Debate 2014; 38:210-24.^,3636. Paiva DCP, Bersusa AAS, Escuder MML. Avaliação da assistência ao paciente com diabetes e/ou hipertensão pelo Programa Saúde da Família do Município de Francisco Morato, São Paulo, Brasil. Cad Saúde Pública 2006; 22:377-85.^,3737. Rosa RS, Schmidt MI, Duncan BB, Souza MFM, Lima AK, Moura L. Internações por Diabetes Mellitus como diagnóstico principal na Rede Pública do Brasil, 1999-2001. Rev Bras Epidemiol 2007; 10:465-78..

This study shares two limitations with all studies on global burden of disease in the world: (i) the scarcity of nationally representative studies that estimate diabetes mellitus prevalence and incidence rates and chronic complications, as well as the duration and proportion of treatments performed and (ii) underreporting and incorrect classification of deaths. Another inherent limitation to the traditional method of Global Burden of Disease Studies is the exhaustive list of complications to be investigated, evidencing the absence of acute complications from the list, notably hypoglycemia and hyperglycemia, since complications are frequent in patients with diabetic nephropathy and result in emergency department visits or even hospitalizations.

The last multicenter study in Brazil on type 2 diabetes mellitus prevalence in the population using diagnostic tests was in 1986-1988. The current study adjusted this estimate according to the prevalence of overweight and obese individuals in the Brazilian population, resulting in a 9.7% rate in adults 30 years or older (10.3% in men and 9.1% in women). Considering the difficulties in correctly classifying the share of deaths from acute myocardial infarction attributed to type 2 diabetes mellitus, in the current study the burden of deaths from acute myocardial infarction was computed in the group of ischemic heart diseases rather than as a type 2 diabetes mellitus-associated comorbidity.

The findings corroborate studies on the relevance of type 2 diabetes mellitus in Brazil and worldwide in recent decades. The YLD rate per 1,000 inhabitants is more than half the rate of the entire group that includes infectious and parasitic diseases, maternal causes, perinatal causes, and nutritional deficiencies. The findings thus have implications for planning actions in the Brazilian health system. Since diabetes is a primary care-sensitive condition, it is hoped that strengthening primary care by including relatively simple preventive and curative measures will positively impact the diagnosis and follow-up of individuals with diabetes, thus preventing diabetes mellitus and chronic complications or delaying the latter's progression, helping to enhance care and quality of life for these patients.

Acknowledgments

The authors wish to acknowledge the professionals that participated in the expert consensus: Alessandro Dorileo Paim, Claudia Ramos Marques da Rocha, Domingos Augusto Cherino Malerbi, Jose Egidio Paulo de Oliveira, Paulo Henrique de Avila Morales, Roberta Coelho, and Roselee Pozzan. We thank Dr. Domingos Augusto Cherino Malerbi for his critical revision of the manuscript, as well as the other members of the Global Burden of Disease project, Brazil 2008: Iúri da Costa Leite and Joaquim Gonçalves Valente.

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