original article
http://www.kidney-international.org & 2008 International Society of Nephrology
High prevalence of chronic kidney disease in Thailand V Perkovic1, A Cass1,2, AA Patel1,2, P Suriyawongpaisal3, F Barzi1, S Chadban2, S MacMahon1 and B Neal1 on behalf of the InterASIA Collaborative Group 1
George Institute for International Health, University of Sydney, Sydney, New South Wales, Australia; 2Royal Prince Alfred Hospital, Sydney, New South Wales, Australia and 3Faculty of Medicine, Mahidol University, Bangkok, Thailand
We describe the prevalence of stage III and IV chronic kidney disease in Thailand from a representative sample of individuals aged 35 years and above using a stratified, multistage, cluster-sampling method. Population estimates were calculated by applying sampling weights from the 2000 Thai census. Glomerular filtration rates were estimated from serum creatinine using the Cockroft–Gault and the simplified Modification of Diet in Renal Disease (MDRD) formulae. The prevalence of stage III disease among individuals aged 35 years and above was estimated to be about 20% using the Cockroft–Gault formula and about 13% from the MDRD formula. Stage IV disease was present in about 0.9 and 0.6% of this population using the respective formulae. The highest prevalence rates were observed in less well-developed rural areas and the lowest in developed urban areas. The prevalence of chronic kidney disease was significantly higher than that reported in individuals over 40 years old from the United States for both stage III and IV disease and higher than the reported incidence in Taiwan and Australia. This high prevalence of chronic kidney disease in Thailand has obvious implications for the health of its citizens and for the allocation of health-care resources. Kidney International (2008) 73, 473–479; doi:10.1038/sj.ki.5002701; published online 5 December 2007 KEYWORDS: chronic kidney disease; MDRD; Cockroft–Gault; prevalence; survey; Thailand
Correspondence: V Perkovic, George Institute of International Health, University of Sydney, PO Box M201, Missenden Road, Sydney, New South Wales 2050, Australia. E-mail:
[email protected] Received 14 July 2006; revised 13 September 2007; accepted 19 September 2007; published online 5 December 2007 Kidney International (2008) 73, 473–479
The presence of chronic kidney disease (CKD) is associated with an increased risk of a multitude of adverse health outcomes, including end-stage kidney disease (ESKD) as well as a substantial reduction in life expectancy.1,2 Therapeutic strategies to reduce the risk of ESKD and other complications in individuals with CKD are now available,3 so early recognition and the institution of proven therapeutic strategies are important. Large population-representative surveys in the United States and Australia have reported the prevalence of CKD in these countries;4,5 however, much less information is available on prevalence rates elsewhere and, in particular, in developing regions.6 Given the limited ability to afford dialysis and the rapidly increasing prevalence of conditions such as diabetes and hypertension that may predispose to the development of CKD, prevention strategies may be especially important in developing regions.7 Thailand is a developing country in Asia with a population of more than 60 million people. The InterASIA study was designed and performed to estimate the prevalence of a variety of diseases in China and Thailand. In this study, we aim to estimate the prevalence of CKD among adults in Thailand. RESULTS Overall
Of the 7909 Thai individuals aged 35 years and above invited to participate in InterASIA, 5303 (67%) took part in this study and creatinine measurements were available for 5146. The characteristics of the participants are shown in Tables 1 and 2. Using the Cockroft–Gault formula, stage III CKD was estimated to be present in 20.1% (95% confidence interval (CI): 16.1–24.1) of Thai individuals aged more than 35 years and stage IV CKD in 0.94% (CI: 0.44–1.44%). This equates to approximately 5.0 million (CI: 4.5–5.5 million) and 230 000 (CI: 110 000–350 000) individuals with stage III and IV CKD, respectively. When the simplified Modification of Diet in Renal Disease (MDRD) formula was used, stage III CKD was present in 13.2% (CI: 10.6–15.8%) of the population and stage IV CKD in 0.61% (CI: 0.29–0.93%), equating to approximately 3.3 473
original article
V Perkovic et al.: The prevalence of kidney disease in Thailand
Table 1 | Estimated mean levels and prevalence of participant characteristics overall and in rural compared to urban Thai adults aged 35 years and older Rural Age (years) Women (%) Serum creatinine (mg per 100 ml) Creatinine clearance (ml min1) GFR (ml min1) Hypertension (4140/90 mm Hg) SBP (mm Hg) DBP (mm Hg) Current smoking (%) Current alcohol consumption (%) Diabetes (%) Height (cm) Weight (kg) Body mass index (kg m2)
50.8 51.3 1.001 76.0 77.1 14.6 119 75 26.8 35.6 8.5 157.1 58.3 23.6
Urban
(1.4) (6.6) (0.016) (1.6) (1.0) (1.0) (1.0) (0.5) (4.4) (3.7) (0.8) (0.6) (0.6) (0.2)
50.2 53.1 0.986 79.6 78.3 23.1 122 78 20.8 33.9 11.9 58.3 62.0 24.7
P-value
(1.5) (7.8) (0.019) (1.7) (1.0) (1.1) (1.2) (0.8) (3.1) (3.2) (1.0) (0.8) (0.8) (0.2)
0.82 0.88 0.67 0.30 0.55 o0.001 0.06 o0.001 0.32 0.76 0.02 0.40 0.001 o0.001
BSA, body surface area; DBP, diastolic blood pressure; GFR, glomerular filtration rate; MDRD, Modification of Diet in Renal Disease; SBP, systolic blood pressure. Values are mean (s.e.) or percent (s.e.). Weighted using sampling factors from the 2000 Thai National Census population. Creatinine clearance calculated using the Cockroft–Gault formula and adjusted for a BSA of 1.73, GFR calculated using the simplified MDRD formula. P-values relate to comparisons between rural and urban populations.
Table 2 | Baseline characteristics of participants according to region Urban Factor Age (years) Women (%) Weight (kg) Height (cm) Body mass index (kg m2) Body surface area (m2) Creatinine (mg per 100 ml) CG CrCl MDRD GFR Diabetes (%) Hypertension (%, 4140/90 mm Hg) SBP (mm Hg) DBP (mm Hg)
Non-slum 50.2 53.1 62.0 158.3 24.7 1.65 0.99 80 78 12.2 26.0 121.9 78.1
(1.7) (8.4) (0.9) (1.0) (0.2) (0.02) (0.02) (3) (1) (1.1) (2.5) (1.3) (0.8)
Rural Slum 50.2 53.0 61.5 157.7 24.7 1.63 0.99 80 79 14.2 26.7 121.6 78.7
(2.0) (10.2) (0.8) (1.2) (0.3) (0.02) (0.03) (2) (2) (1.7) (3.0) (1.5) (0.8)
Developed
Developing
50.9 50.6 59.1 157.3 23.9 1.60 0.99 77 78 9.9 19.8 119.3 75.0
50.6 52.8 56.2 156.6 22.9 1.56 1.02 73 75 7.0 13.0 116.7 73.2
(1.9) (9.0) (0.8) (1.1) (0.3) (0.01) (0.03) (3) (2) (1.2) (2.7) (1.3) (0.7)
(2.4) (12.0) (0.8) (1.2) (0.3) (0.02) (0.03) (3) (2) (1.2) (2.3) (1.2) (0.5)
Undeveloped 50.9 60.8 54.8 153.9 23.0 1.53 1.05 70 72 5.1 17.9 118.0 73.9
(3.9) (18) (2.4) (1.7) (0.9) (0.04) (0.05) (5) (3) (1.2) (5.7) (3.0) (1.3)
P-value 0.99 0.98 o0.0001 0.25 o0.0001 0.004 0.76 0.15 0.22 0.03 0.01 0.026 o0.0001
BSA, body surface area; DBP, diastolic blood pressure; GFR, glomerular filtration rate; MDRD, Modification of Diet in Renal Disease; SBP, systolic blood pressure. Values are mean (s.e.) or percent (s.e.). Weighted using sampling factors from the 2000 Thai National Census population. Creatinine clearance calculated using the Cockroft–Gault formula and adjusted for a BSA of 1.73, GFR calculated using the simplified MDRD formula. Diabetes defined as known diabetes or fasting plasma glucose 4126 mg per 100 ml.
million (CI: 2.6–3.9 million) and 150 000 (CI: 70 000–230 000) individuals, respectively. The distribution of kidney function overall and in major population subgroups is shown in Table 3. A direct relationship was observed between age and CKD prevalence. Development status. The proportion of individuals with CKD in population groups defined by their development status is shown in Figure 1 and their characteristics in Table 2. The prevalence of CKD was progressively higher across non-slum urban, slum urban, developed rural, developing rural, and undeveloped rural populations. Participants in less developed regions tended to be smaller and thinner but had higher serum creatinine levels (Table 2). The prevalence of hypertension was lower in less developed regions (P ¼ 0.01), and a lower prevalence of diabetes was observed than in more highly developed regions (P ¼ 0.03). 474
The prevalence of CKD by development status was assessed separately for individuals with and without diabetes and hypertension (Figure 2). The prevalence of CKD decreased with increasing development status in people with and without hypertension and in those who did not have diabetes. No clear relationship was observed between development status and CKD prevalence for individuals with diabetes. Comparison to the United States, Australia, and Taiwan
The estimated prevalence rates of stage III and IV CKD in age- and sex-stratified subgroups of the United States, Taiwanese, and Australian populations have been published recently.4,5,8 The creatinine measurements from the InterASIA study were standardized using a common laboratory for the US data to allow direct comparison of results for these Kidney International (2008) 73, 473–479
original article
V Perkovic et al.: The prevalence of kidney disease in Thailand
Table 3 | Distribution of CKD stages overall and within subgroups of the Thai population GFR prevalence Subgroup
No. of participants
% of Thai population 100
490
60–89
30–59
o30
22.0 (1.5)
64.0 (1.4)
13.4 (1.3)
0.6 (0.2)
Overall
5146
Gender Men Women
2018 3081
48.7 51.3
23.5 (2.0) 20.6 (2.2)
64.3 (1.6) 63.7 (2.1)
11.5 (1.5) 15.1 (2.1)
0.7 (0.3) 0.6 (0.2)
Location Urban Rural
3035 2064
32.3 67.7
22.4 (1.9) 21.8 (2.0)
65.7 (1.3) 63.2 (1.9)
11.2 (1.4) 14.4 (1.7)
0.6 (0.2) 0.7 (0.2)
Region Bangkok North Northeast Central South
989 1015 1072 1033 990
10.9 22.1 28.9 25.2 12.9
22.5 25.4 18.1 23.6 21.7
(3.5) (4.7) (2.1) (2.6) (3.8)
67.9 59.7 64.9 62.7 68.6
(2.3) (3.3) (3.0) (1.4) (2.6)
9.6 13.6 16.4 13.3 9.4
(2.7) (2.1) (3.3) (2.3) (2.4)
0.1 1.5 0.5 0.4 0.3
(0.1) (0.5) (0.3) (0.3) (0.2)
Age (years) 35–44 45–54 55–64 65+
1548 1360 1181 1057
40.8 26.6 17.2 15.4
35.0 21.4 8.7 3.5
(2.5) (2.0) (1.2) (1.0)
62.8 70.3 67.7 52.1
(2.4) (2.2) (2.3) (2.9)
2.1 8.2 22.6 41.8
(0.5) (0.9) (2.3) (3.2)
0.1 0.1 1.1 2.6
(0.1) (0.1) (0.4) (0.9)
Diabetes No Yes
4478 615
90.3 9.7
22.3 (1.6) 19.4 (3.3)
65.4 (1.4) 50.7 (3.3)
11.9 (1.2) 26.7 (2.8)
0.4 (0.1) 3.0 (1.4)
Hypertension No Yes, no medication Yes, medication
3783 873 443
78.8 14.6 6.6
24.3 (1.7) 17.0 (2.4) 6.0 (2.5)
64.8 (1.6) 63.8 (2.4) 54.5 (3.8)
10.4 (1.3) 18.2 (2.1) 37.5 (3.7)
0.5 (0.1) 1.0 (0.5) 2.0 (1.0)
CKD, chronic kidney disease; GFR, glomerular filtration rate; MDRD, Modification of Diet in Renal Disease. The simplified MDRD formula was used to estimate GFR.
30 CrCl
