the prevalence of diabetes is increasing rapidly worldwide with the influence of expanding economy , abrupt transition of living styles , and social aging . in 2014 , there were 387  million people living with diabetes worldwide .
the number is predicted to reach 592  million by 2035 of which 46% will still be un - diagnosed . throughout the world , there exists a large amount of diversity with respect to diabetes prevalence , deaths , and health expenditure . according to the 6th edition ( 2014 update ) of the international diabetes federation ( idf ) diabetes atlas , the western pacific ( wp ) has the largest population with diabetes ( 137.8  million ) , which means that 7.9% of the population in this region has diabetes .
the region with the second highest prevelance is southeast asia ( sea ) with 75.0  million patients ( table  1 ) .
another fact of spatial distribution is that the prevalence rate of diabetes in developing countries is higher .
more than 80% of diabetic patients live in low- and middle - income countries . globally , 90% of diabetic patients have type 2 diabetes , of which 77% live in developing countries [ 4 , 5 ] . in china ,
the number of diabetes patients in china was 96.3  million , 29.5  million more compared to india , in 2014 .
the prevalence rate of diabetes had reached 9.3% .table  1regional estimates for diabetes ( 2079  years old ) in 2014idf regionpopulation ( millions)number of people with diabetes ( millions)comparative diabetes prevalence ( % ) afr407.921.55.9eur658.752.06.2mena374.536.811.3nac334.938.89.9saca300.524.88.2sea883.275.08.8wp1,613.2137.87.9world4,572.9386.78.2 
 idf international diabetes federation , afr africa , eur europe , mena middle east and north africa , nac north america and caribbean , saca south and central america , sea southeast asia , wp western pacific regional estimates for diabetes ( 2079  years old ) in 2014 
 idf international diabetes federation , afr africa , eur europe , mena middle east and north africa , nac north america and caribbean , saca south and central america , sea southeast asia , wp western pacific china carried out five large - scale epidemiological surveys to understand better the prevalence of type 2 diabetes .
the prevalence rate of diabetes has been increasing in china from 0.67% in 1980 , 2.51% in 19941995 , 3.21% in 1996 , 3.31% in 2002 , and 9.7% in 20072008 . according to these survey results ,
the morbidity rate of type 2 diabetes mellitus accounted for 93.70% of all types of diabetes in china where socioeconomic status seems to have influenced the prevalence rate .
the prevalence of pre - diabetes among the rural population ( 16.6% ) is far greater compared to urban ( 13.6% ) .
in addition , the high mortality of diabetes and related complications is also a huge challenge .
the premature mortality of patients with diabetes is mostly attributable to related complications , not uniquely related to the condition .
it was recorded in  the global burden of disease : 2004 update  that 508,000 men and 633,000 women died from direct diabetes - related causes , accounting for 1.6% and 2.3% of all deaths in the world , respectively .
the international diabetes federation in 2007 reported diabetes - related deaths to be 6% of total global mortality in the population aged 2079  years .
statistics from 2013 assessed 5,096,955 diabetes - related deaths in 2079  year - olds in the world , of which 1,271,003 were recorded in china .
the mortality of diabetes is strongly related to age . in patients with type 2 diabetes under 35  years
this rate decreases to 59% among 3564  year - olds , and 29% at 64  years or older .
given the high prevalence rate and mortality rate , understanding the disease burden of diabetes is the first step when formulating an effective control strategy for governments and international organizations .
data from 2013 estimates that worldwide diabetes will contribute $ 548  billion in health expenditures ( 11% of the total health expenditure ) and $ 1,437 per person on treating and managing the disease .
the estimated health expenditure was $ 5,621 per person in high - income countries , compared to $ 356 in low- and middle - income countries . in 2013 , the usa spent $ 239 billion on diabetes , or 36% of global health expenditure , meanwhile , china spent just $ 38 billion , less than 7% of the global total in the same year .
the direct burden deals with health resource consumption , such as drug cost , outpatient cost , inpatient cost , and inspection cost .
the indirect burden encompasses monetary losses resulting from opportunity costs caused by death , disability , and incapacitation .
the indirect burden also includes the transportation expenses incurred by patients and their families , accommodation expenses , nutrition costs of patients , social productivity losses , income losses , and housework labor force losses ( non - market productivity losses ) . as we know
thus , the objective of this study is to synthesize and analyze the costs of type 2 diabetes .
it aims to answer two key questions : ( 1 ) document economic burden of type 2 diabetes in china .
( 2 ) identify main factors affecting the economic burden of type 2 diabetes in china .
this is a systematic review study . the main english databases , including pubmed and ebsco , and the chinese databases , including wanfang data , china national knowledge infrastructure ( cnki ) , and the china science and technology journal database , were explored for relevant articles with the following combination of keywords : ( diabetes mellitus and type 2 ) and ( cost of illness or illness burden or cost of disease or economic burden of disease ) . the last search was conducted on june 30 , 2013 . in the searching , studies considered for this review were english- and chinese - language articles from peer - reviewed publications which focused on the evaluation of the direct economic burden of type 2 diabetes in china and on the comparison between china and other developed countries .
inclusion criteria : estimation of the direct and indirect medical cost , hospitalization cost , and outpatient fee for type 2 diabetes patients in china;evaluation of factors influencing direct and indirect medical cost , hospitalization costs , and outpatient fee in china .
estimation of the direct and indirect medical cost , hospitalization cost , and outpatient fee for type 2 diabetes patients in china ; evaluation of factors influencing direct and indirect medical cost , hospitalization costs , and outpatient fee in china .
exclusion criteria : articles that focused on the effectiveness evaluation of the diabetic drugs were ineligible for this review .
a total of 377 original citations were identified that met all the inclusion and exclusion criteria .
after further review and elimination of duplicates , 39 studies ( full text ) were included for final analysis . this review article is based on previously conducted studies and does not involve any new studies of human or animal subjects performed by any of the authors .
the main english databases , including pubmed and ebsco , and the chinese databases , including wanfang data , china national knowledge infrastructure ( cnki ) , and the china science and technology journal database , were explored for relevant articles with the following combination of keywords : ( diabetes mellitus and type 2 ) and ( cost of illness or illness burden or cost of disease or economic burden of disease ) . the last search was conducted on june 30 , 2013 . in the searching ,
studies considered for this review were english- and chinese - language articles from peer - reviewed publications which focused on the evaluation of the direct economic burden of type 2 diabetes in china and on the comparison between china and other developed countries .
inclusion criteria : estimation of the direct and indirect medical cost , hospitalization cost , and outpatient fee for type 2 diabetes patients in china;evaluation of factors influencing direct and indirect medical cost , hospitalization costs , and outpatient fee in china .
estimation of the direct and indirect medical cost , hospitalization cost , and outpatient fee for type 2 diabetes patients in china ; evaluation of factors influencing direct and indirect medical cost , hospitalization costs , and outpatient fee in china .
exclusion criteria : articles that focused on the effectiveness evaluation of the diabetic drugs were ineligible for this review .
a total of 377 original citations were identified that met all the inclusion and exclusion criteria .
after further review and elimination of duplicates , 39 studies ( full text ) were included for final analysis .
this review article is based on previously conducted studies and does not involve any new studies of human or animal subjects performed by any of the authors .
according to table  2 , in china , the direct medical cost of type 2 diabetes in proportion to the gross domestic product ( gdp ) increased gradually year by year . in 1993 , it was reported that direct medical cost was $ 0.25 billion , accounting for 0.07% of the gdp . in 2002 ,
a national survey in 11 major cities indicated that the direct medical cost had increased $ 2.27 billion , and the percentage of direct medical cost in the gdp was 0.18% .
some studies concluded , after comparing several national surveys , that the average annual growth rate of the direct medical cost of type 2 diabetes was 19.90% which was more than the average annual growth rate of the gdp ( 12.77% ) and the national health expenditure ( 12.88% ) from 1993 to 2003 .
more alarmingly , when it came to 2008 , the direct medical cost already increased to $ 8.65 billion , accounting for 0.21% of the gdp .table  2the medical cost of type 2 diabetes in chinareferencesdataout - patient costin - patient costdirect medical cost ( billion dollars)direct medical cost over the gdp ( % ) shen hongbin 1st national health service survey ; multi - stage cluster random samplingthe annual total outpatient cost was $ 0.22 billion ; the average outpatient expense at a visit was $ 12.41 the annual total in - patient cost was $ 0.03 billion ; the average inpatient expense at a visit was $ 248.97 0.250.07tang ling nationwide survey in 11 major citiesthe average out - patient expense at a visit was $ 31.5670.25 ( according to whether or not it has complications)the average in - patient expense at a visit was $ 595.411999.76 ( according to whether or not it has complications)2.270.18hu jianping 3rd national health service survey ; multi - stage cluster random samplingthe annual total out - patient cost was $ 1.06 billion the annual total in - patient cost was $ 0.89 billion 2.130.15wang jiansheng 3rd national health service survey ; multi - stage cluster random samplingthe annual total out - patient cost was $ 0.86 billion the annual total in - patient cost was $ 0.44 billion 1.300.10li lina 4th national health service survey ; multi - stage cluster random samplingthe annual total out - patient cost was $ 5.53 billion the annual total in - patient cost was $ 3.13 billion 8.650.21 the medical cost of type 2 diabetes in china the direct medical cost included outpatient cost and inpatient cost ( hospitalization cost ) . referring back to table  2 ,
the annual total outpatient and inpatient costs were $ 0.22 billion and $ 0.03 billion , respectively , in 1993 . and in 2008
, they had risen to $ 5.53 billion and $ 3.13 billion , respectively . according to a national survey on the economic burden of type 2 diabetes in china from 2007 to 2008 ,
the average outpatient cost per person at a visit was $ 46.22 in urban areas .
in rural areas , the average outpatient cost per person at a visit was $ 54.73 .
the average inpatient cost per person at a visit was $ 2,222.77 in urban areas , $ 1,420.30 more than the normal population .
in rural areas , the annual inpatient cost per person at a visit was $ 499.73 .
although the annul total outpatient cost was more than the total inpatient cost , the average inpatient cost per person at a visit was much more than the average outpatient cost per person at a visit .
thus , most studies focusing on the economic burden of diabetes highlight the proportion of hospitalization cost in direct medical cost as the highest . in recent years
, the prevalence of type 2 diabetes in china has also risen rapidly , leading to higher hospitalization cost in direct medical cost , from 12.91% in 1993   to 44.74% in 2003 .
the direct non - medical cost has also been increasing in recent years , including transportation of patients and their families , accommodation expenses , and nutrition costs of patients .
the average direct non - medical cost per inpatient in urban and rural areas was $ 0.73 and 0.48 , respectively in 1998 . by 2003
in 2008 , the same cost escalated to $ 2.74 and 2.04 in urban and rural areas , respectively .
inpatient average direct non - medical cost per patient in urban areas jumped from $ 81.02 to 96.84 from 1998 to 2008 , and from $ 39.18 to 71.74 in rural areas [ 2426 ] .
the direct medical cost accounts for the majority of the economic burden . in recent years
, there has been a rapid increase in hospitalization , which has contributed to the high overall direct medical cost .
factors influencing hospitalization cost include hospital stay , income level , types of medical insurance , level of hospital , and type and number of complications .
hospitalization stay for diabetes patients is two times longer than non - diabetics [ 27 , 28 ] , and the length of hospital stay for diabetics has been increasing in the last 5  years .
in shangdong province , the hospitalization stay increased from 10.43  days in 2005 to 16.79  days in 2010 .
according to a national survey on the economic burden of type 2 diabetes in china in 20072008 , the hospitalization stay of diabetic patients was double the normal population .
patients with high income tend to accept a more expensive and longer - term therapy strategy .
, patients mainly have four types of medical insurance , including new rural cooperative medical system ( ncms ) , medical insurance for urban workers , medical insurance for urban residents , and  out - of - pocket  payment .
the average hospitalization cost per patient with medical insurance for urban workers ( $ 1,094.53 ) was more than that with medical insurance of urban residents ( $ 1,065.50 ) , ncms ( $ 558.01 ) , and  out - of - pocket  payments ( $ 609.65 ) in 20052010 .
in china , the hospitals are mainly divided into three levels including the tertiary hospital , the secondary hospital , and the primary hospital , based on their function , mission , facility , technology , quality of medical services , and scientific management . comparing the medical expenditure in the three levels of hospital , the higher the level that patients stayed , the more money patients paid .
the hospitalization cost increases with the number of complications . of patients with a diagnosis of diabetes ,
treatment cost of patients with complications shows a linear relationship where cost was 3.36 times higher for patients with complications compared to those without complications .
the complications resulting in a severe state of illness thus also increase the frequency of physical examinations and laboratory tests . to deal with these situations better , doctors prescribe use of better drugs or increase the doses for quick relief of associated symptoms , which has led to a difference in hospitalization costs among patients with different conditions .
medical expenditure of patients with microvascular or macrovascular disease or with both was higher than for those without , with an increase of 1.46 , 1.75 , and 2.38 times , respectively .
the average hospitalization cost of a patient with diabetic nephropathy was the highest followed by diabetic foot , and then cerebral infarction or cerebral hemorrhage .
the average hospitalization cost per patient with diabetic nephropathy ( dialysis patients ) , diabetic nephropathy ( non - dialysis patients ) , and diabetic foot was $ 2,446.6 , 1,672.5 , and 2,305.5 , respectively .
according to table  2 , in china , the direct medical cost of type 2 diabetes in proportion to the gross domestic product ( gdp ) increased gradually year by year . in 1993 , it was reported that direct medical cost was $ 0.25 billion , accounting for 0.07% of the gdp . in 2002 ,
a national survey in 11 major cities indicated that the direct medical cost had increased $ 2.27 billion , and the percentage of direct medical cost in the gdp was 0.18% .
some studies concluded , after comparing several national surveys , that the average annual growth rate of the direct medical cost of type 2 diabetes was 19.90% which was more than the average annual growth rate of the gdp ( 12.77% ) and the national health expenditure ( 12.88% ) from 1993 to 2003 .
more alarmingly , when it came to 2008 , the direct medical cost already increased to $ 8.65 billion , accounting for 0.21% of the gdp .table  2the medical cost of type 2 diabetes in chinareferencesdataout - patient costin - patient costdirect medical cost ( billion dollars)direct medical cost over the gdp ( % ) shen hongbin 1st national health service survey ; multi - stage cluster random samplingthe annual total outpatient cost was $ 0.22 billion ; the average outpatient expense at a visit was $ 12.41 the annual total in - patient cost was $ 0.03 billion ; the average inpatient expense at a visit was $ 248.97 0.250.07tang ling nationwide survey in 11 major citiesthe average out - patient expense at a visit was $ 31.5670.25 ( according to whether or not it has complications)the average in - patient expense at a visit was $ 595.411999.76 ( according to whether or not it has complications)2.270.18hu jianping 3rd national health service survey ; multi - stage cluster random samplingthe annual total out - patient cost was $ 1.06 billion the annual total in - patient cost was $ 0.89 billion 2.130.15wang jiansheng 3rd national health service survey ; multi - stage cluster random samplingthe annual total out - patient cost was $ 0.86 billion the annual total in - patient cost was $ 0.44 billion 1.300.10li lina 4th national health service survey ; multi - stage cluster random samplingthe annual total out - patient cost was $ 5.53 billion the annual total in - patient cost was $ 3.13 billion 8.650.21 the medical cost of type 2 diabetes in china the direct medical cost included outpatient cost and inpatient cost ( hospitalization cost ) . referring back to table  2 ,
the annual total outpatient and inpatient costs were $ 0.22 billion and $ 0.03 billion , respectively , in 1993 . and in 2008
, they had risen to $ 5.53 billion and $ 3.13 billion , respectively . according to a national survey on the economic burden of type 2 diabetes in china from 2007 to 2008 ,
the average outpatient cost per person at a visit was $ 46.22 in urban areas .
in rural areas , the average outpatient cost per person at a visit was $ 54.73 .
the average inpatient cost per person at a visit was $ 2,222.77 in urban areas , $ 1,420.30 more than the normal population .
in rural areas , the annual inpatient cost per person at a visit was $ 499.73 .
although the annul total outpatient cost was more than the total inpatient cost , the average inpatient cost per person at a visit was much more than the average outpatient cost per person at a visit .
thus , most studies focusing on the economic burden of diabetes highlight the proportion of hospitalization cost in direct medical cost as the highest . in recent years
, the prevalence of type 2 diabetes in china has also risen rapidly , leading to higher hospitalization cost in direct medical cost , from 12.91% in 1993   to 44.74% in 2003 .
the direct non - medical cost has also been increasing in recent years , including transportation of patients and their families , accommodation expenses , and nutrition costs of patients .
the average direct non - medical cost per inpatient in urban and rural areas was $ 0.73 and 0.48 , respectively in 1998 . by 2003
, it increased to $ 0.97 , for both urban and rural areas . in 2008 ,
the same cost escalated to $ 2.74 and 2.04 in urban and rural areas , respectively .
inpatient average direct non - medical cost per patient in urban areas jumped from $ 81.02 to 96.84 from 1998 to 2008 , and from $ 39.18 to 71.74 in rural areas [ 2426 ] .
the direct medical cost accounts for the majority of the economic burden . in recent years
, there has been a rapid increase in hospitalization , which has contributed to the high overall direct medical cost .
factors influencing hospitalization cost include hospital stay , income level , types of medical insurance , level of hospital , and type and number of complications .
hospitalization stay for diabetes patients is two times longer than non - diabetics [ 27 , 28 ] , and the length of hospital stay for diabetics has been increasing in the last 5  years .
in shangdong province , the hospitalization stay increased from 10.43  days in 2005 to 16.79  days in 2010 .
this increase leads to an increase in hospitalization expenditure . according to a national survey on the economic burden of type 2 diabetes in china in 20072008 ,
patients with high income tend to accept a more expensive and longer - term therapy strategy .
, patients mainly have four types of medical insurance , including new rural cooperative medical system ( ncms ) , medical insurance for urban workers , medical insurance for urban residents , and  out - of - pocket  payment .
the average hospitalization cost per patient with medical insurance for urban workers ( $ 1,094.53 ) was more than that with medical insurance of urban residents ( $ 1,065.50 ) , ncms ( $ 558.01 ) , and  out - of - pocket  payments ( $ 609.65 ) in 20052010 .
the level of hospital also had an important influence on hospitalization costs . in china ,
the hospitals are mainly divided into three levels including the tertiary hospital , the secondary hospital , and the primary hospital , based on their function , mission , facility , technology , quality of medical services , and scientific management . comparing the medical expenditure in the three levels of hospital , the higher the level that patients stayed , the more money patients paid .
the hospitalization cost increases with the number of complications . of patients with a diagnosis of diabetes ,
treatment cost of patients with complications shows a linear relationship where cost was 3.36 times higher for patients with complications compared to those without complications .
the complications resulting in a severe state of illness thus also increase the frequency of physical examinations and laboratory tests . to deal with these situations better , doctors prescribe use of better drugs or increase the doses for quick relief of associated symptoms , which has led to a difference in hospitalization costs among patients with different conditions .
medical expenditure of patients with microvascular or macrovascular disease or with both was higher than for those without , with an increase of 1.46 , 1.75 , and 2.38 times , respectively .
the average hospitalization cost of a patient with diabetic nephropathy was the highest followed by diabetic foot , and then cerebral infarction or cerebral hemorrhage .
the average hospitalization cost per patient with diabetic nephropathy ( dialysis patients ) , diabetic nephropathy ( non - dialysis patients ) , and diabetic foot was $ 2,446.6 , 1,672.5 , and 2,305.5 , respectively .
most of them are 4060  years old , and the prevalence rate increases gradually after 40  years old .
the direct economic burden of type 2 diabetes is increasing over time , with the yearly increment affecting the direct medical costs to gdp ratio .
the average annual growth rate of the direct medical cost of type 2 diabetes is proportionately more than the average annual growth rate of the gdp and the national health expenditure .
the direct medical cost of diabetes in china has approached , or in some instances even exceeded , some developed countries .
thus , we focused on the direct economic burden of type 2 diabetes . as was mentioned above , hospitalization cost plays a decisive role in direct medical costs .
the factors affecting hospitalization cost are income level , type of medical insurance , level of hospital , and related complications .
but the relationship between the hospitalization cost and the hospital level needed a further explanation .
the tertiary hospitals provide high - level specialist  medical services , teaching and research .
the secondary one has a full complement of services including pediatrics , obstetrics , general medicine , gynecology , and various branches of surgery and psychiatry .
the high level hospitals often charge more for examination services and drugs than the low level hospitals .
in addition , based on the essential drug system , the doctors in different level hospitals had different prescription  privileges in china .
the doctor in primary hospitals can just prescribe limited drugs which were included in the essential drug list .
it is known that drugs are the main form of treatment for controlling blood glucose and glycosylated hemoglobin and is a significant contributor of costs for diabetes and related causes .
because of the economic growth and more purchasing power , patients are willing to choose more expensive medications primarily because they think the price of the drug is associated with its effectiveness .
changes in living environment and corresponding lifestyle are major reasons for the increase in prevalence of type 2 diabetes patients .
more and more people tend to enjoy unhealthy foods and with reduced engagement in physical activities ; most people are subjected to regular intake of high - calorie , high - fat , and high - protein foods . incorporating measures related to health education can help reduce the prevalence of diabetes . designing and implementing cost - effective diagnosis and treatment tools can help to deal with hospitalization and drug costs better .
type 2 diabetes is presently a major contributor of overall health care cost mainly due to poor knowledge about the disease among populations and the time difference between the onset of disease and treatment .
the sooner the disease can be diagnosed , the less expensive the treatment and the cost for associated complications , which will further result in efficiency in providing simpler treatments , thus reducing the overall cost [ 41 , 42 ] .
therefore , the methods for early screening , early diagnosis , and early treatment are necessary for follow - up , management , and monitoring in communities . in this study
, we mainly focus on the direct costs related to diabetes , but not the indirect costs because literature is lacking .
in addition , diabetes can also result in big disease burdens for people in the form of disability - adjusted life years ( dalys ) , thus both indirect economic burden and disease burden need further study .
the direct medical burden of type 2 diabetes is a grave economic problem in china .
measures need to be taken to reduce prevalence rate , hospitalization cost , and drug cost in order to reduce the resulting economic burden .
because of the higher economic burden associated with rural areas of china , more rigorous interventions should be considered in these areas .
huimei hu , monika sawhney , lizheng shi , shengnanduan , yunxian yu , zhihong wu , guixingqiu , hengjin dong declare they have no conflict of interest .
this review is based on previously conducted studies , and does not involve any new studies of human or animal subjects performed by any of the authors .
this article is distributed under the terms of the creative commons attribution noncommercial license which permits any noncommercial use , distribution , and reproduction in any medium , provided the original author(s ) and the source are credited .
 backgroundtype 2 diabetes is associated with acute and chronic complications and poses a large economic , social , and medical burden on patients and their families as well as society.objectivethis study aims to evaluate the direct economic burden of type 2 diabetes in china . 
 data source : systematic review on cost of illness , health care costs , direct service costs , drug costs , and health expenditures in relation to type 2 diabetes was conducted up to 2014 using databases such as pubmed ; ebsco ; elsevier sciencedirect , web of science ; and a series of chinese databases , including wanfang data , china national knowledge infrastructure ( cnki ) , and the china science and technology journal database . factors influencing hospitalization and drug fees were also identified . 
 study eligibility criteria : ( 1 ) estimation of the direct economic burden including hospitalization and outpatient cost of type 2 diabetes patients in china ; ( 2 ) evaluation of the factors influencing the direct economic burden . 
 articles only focusing on the cost - effectiveness analysis of diabetes drugs were excluded.resultsthe direct economic burden of type 2 diabetes has increased over time in china , and in 2008 , the direct medical cost reached $ 9.1  billion , both outpatient and inpatient costs have increased . 
 income level , type of medical insurance , the level of hospital care , and type and number of complications are primary factors influencing diabetes related hospitalization costs . compared to urban areas , the direct non - medical cost of type 2 diabetes in rural areas is significantly greater.conclusionsthe direct economic burden of type 2 diabetes poses a significant challenge to china . to address the economic burden associated with type 2 diabetes , measures need to be taken to reduce prevalence rate and severity of diabetes and hospitalization cost . 
Introduction
Methods
Data Sources and Search Strategies
Inclusion Criteria and Exclusion Criteria
Results
The Direct Medical Costs
The Direct Non-Medical Costs
Factors Influencing Direct Medical Cost
Discussion
Conclusion
Conflict of interest
Compliance with ethics
Open Access