Patients with diabetes as the primary kidney disease have a worse survival
than patients with comorbid diabetes in chronic hemodialysis patients
Hung-Chih Chen1, Che-Yi Chou1,2, Chih-Chia Liang1,2, Huey-Liang Kuo1,2, Chiz-Tzung Chang1,2, Jiung-Hsiun Liu1,2, I.-Kuan Wang1,2, Chiu-Ching Huang1,2
1Kidney Institute and Division of Nephrology, Department of Internal Medicine, China Medical University Hospital, Taichung 40447, Taiwan
2College of Medicine, China Medical University, Taichung 40402, Taiwan 3Biostatistics Center, China Medical University, Taichung 40402, Taiwan
Correspondence: Chiu-Ching Huang, MD Address of corresponding author
Kidney Institute and Division of Nephrology, Department of Internal Medicine, China Medical University Hospital, No.2, Yu-der Road, North District, Taichung 40447, Taiwan Tel: +886-4-22052121-2902
Fax: +886-4-22076863
E-mail: [email protected]
Word counts: abstract 249, text 1951
Keywords: hemodialysis, mortality, fasting blood glucose, diabetic kidney disease, comorbidity
Abstract Aim
Diabetes is the leading cause of chronic kidney disease (CKD) that required dialysis. It is not clear if survival of patients with diabetes as primary kidney disease (DKD) is different from the survival of patients with diabetes as comorbidity (DCM). We investigated the survival of patients with DKD and patients with DCM in patients on maintenance hemodialysis (HD) using propensity score matching approach.
Methods
All patients on maintenance HD in Taiwan Renal Registry Database from 1997 to 2005 were analyzed and were prospectively followed to December 31, 2008. Patients’ survival was determined using Cox proportional-hazards regression.
Results
We analyzed the survival of 2632 patients with DCM and 13160 matched patients with DKD. The first year mortality rate was 11.9% in patients with DCM and 13.9% in patients with DKD. The incidence density rate of overall mortality was 11.2 per 100 patient-years in patients with DCM and 12.9 in patients with DKD. Patients with DKD had a worse survival than patients with DCM (p<0.01). Compared to patients with DCM, the odds ratio [95% confidence interval (CI)] for first year mortality was 1.27 (1.10-1.47) and the hazard ratio for overall mortality was 1.18 (1.12-1.25) in patients with DKD. Patients’ age, male gender, comorbid liver cirrhosis, higher fasting blood glucose, lower hematocrit, and lower serum phosphorus were independently associated with higher mortality.
Conclusions
Patients with diabetes as primary kidney disease are associated with higher first year and overall mortality, compared to patients with diabetes as comorbidity in patients on maintenance hemodialysis.
Diabetes was the leading cause of chronic kidney disease that required dialysis . The prevalence of diabetes related kidney disease (CKD) was increased in the last decade with the increasing prevalence of diabetes in general population . Diabetes and diabetes-related disease were associated with higher overall and cardiovascular mortality in general population and in patients with CKD 9. The complications of diabetes include
hyperlipidemia, neuropathy, retinopathy, coronary artery disease (CAD), cerebral vascular accident (CVA) and nephropathy 9-12. Diabetes associated kidney disease was usually
considered as a late complication of diabetes and was developed after neuropathy and retinopathy 13. Relatively enlarged kidneys were common in patients with diabetes as primary
kidney disease and were associated poor outcomes 14. This suggested that patients with
diabetes as primary kidney disease (DKD) may be associated with poor clinical outcomes than patients with diabetes as comorbidity (DCM). However, inconsistent results were found in the previous studies. No differences were found in one of Schroijen et als’ studies that compared the survival of patients with DKD and patients with DCM in Dutch dialysis patients 15. In this study, 22% patients had diabetic and the percentage of patients with
diabetes was lower than the prevalence (30-40%) usually found in most CKD population . Patients’ basal characteristics were different in patients with DKD and patients with DCM, such as the higher rate of CAD and HD in patients with DCM that may affect the results. In another study by Schroijen et al, patients with DKD was associated with worse outcomes using data from European Renal Association–European Dialysis and Transplant Association Registry18. Propensity score matching was not used in both study This study was conducted to
prove our clinical observations and survival of patients with DKD and patients with DCM was analyzed using Taiwan Renal Registry data. A propensity score matching approach was applied to minimize the effect of patients’ basal characteristics on patients’ outcomes.
Methods
This study was approved by the institute review broad China Medical University Hospital (DMR098-IRB-093). The data was obtained from Taiwan Renal Registry Database. The Taiwan Renal Registry was initially funded by the Department of Health, Taiwan in 1987. Information on all patients receiving dialysis from all dialysis units was initially collected every year. Currently, it is a nationwide, non-government system, supervised by the Taiwan Society of Nephrology. Its data collection covers up to 95 percent of all dialysis patients in Taiwan. This is a prospective observational cohort using Taiwan Renal Registry Database including 85439 patients on renal replacement therapy from 1995 to 2005. Data of these subjects who are older than 20 years old and HD for at least 90 days with a complete laboratory data available were collected. All patients were followed to the date of death or December 31, 2008. Date of death was determined using death registration database of Ministry of Interior, Taiwan. Patients who were transferred to peritoneal dialysis and/or kidney transplantation were censored and were followed to the date of the date of transfer. The cause of primary kidney disease including diabetes, chronic glomerular nephritis (CGN), or hypertension was diagnosed by the physician of nephrology at the initiation of HD. Coronary artery disease (CAD) was defined as a positive exercise test, angiographic findings of at least one stenosis of more than 50%, or positive findings on scintigraphy19. Diabetes was
defined as use of insulin, use of a hypoglycemic agent, or a fasting plasma glucose level of 126 mg/dl or more20. Hypertension was defined as taking anti-hypertensives without regard to
the actual measurement of blood pressure, or having a systolic blood pressure reading greater than 140 mm Hg or a diastolic blood pressure reading greater than 90 mmHg21. Patients
reported comorbid cerebral vascular accident (CVA), liver cirrhosis, and any type of cancer were recorded at the initiation of HD. The comorbidities were CAD, diabetes, hypertension, CVA, liver cirrhosis, and cancer. The number of comorbidity was recorded accordingly.
Blood samples were obtained using uniform techniques and measured by automated analyzers in all dialysis facilities. FBG was obtained monthly in diabetic patients and every 3 months in non-diabetic patients. Hematocrit, serum albumin, phosphorus, calcium was obtained monthly and intact parathyroid hormone (iPTH) was obtained every 3 months. For patients with more than two values available, the average value was used.
Statistical analysis
Data are reported as mean ± SD, median, (interquartile range), or percent frequency, as appropriate. Testing for statistical significance as conducted using Student’s t-test for parametric variables and Mann-Whitney U test for non-parametric variables. Propensity score matching based on patients’ age, gender, number of comorbidity, comorbid hypertension, comorbid CAD, comorbid CVA, comorbid liver cirrhosis, comorbid cancer, hematocrit and albumin. Survival of patients with DKD and patients with DCM was analyzed using Kaplan-Meier analysis. All possible confounders including gender, age, the number of comorbidity, DKD, hematocrit, FBG, serum albumin, phosphorus, calcium, calcium-phosphorous product and iPTH was analyzed using logistic regression for first year mortality and Cox proportional hazard regression for overall mortality. The logistic regression and the Cox proportional hazard regression was performed in univariable analysis and confounders with a p < 0.05 were further analyzed in multivariable regressions. An odds ratio (OR) and 95% confidence interval (95% CI) of OR were calculated in logistic regression. A hazard ratio (HR) and 95% CI of HR were calculated in the Cox proportional hazard regression. All statistical analyses were performed with SPSS version 18 (SPSS Inc, Chicago, IL, USA).
Results
with DKD and 2765 patients with DCM (Figure 1). A propensity score matching using patients’ age, gender, number of comorbidity, hypertension, CAD, CVA, liver cirrhosis, cancer, hematocrit, and albumin at the initiation of HD was applied with a ratio of 1:5. A total of 2632 DCM patients and 13160 DKD patients were analyzed. Patients’ age, gender, number of comorbidity, hypertension, CAD, CVA, liver cirrhosis, cancer, hematocrit, and albumin were not different in DKD and DCM patients (Table 1). FBG was higher and iPTH was lower in DKD patients. First year mortality was 13.9% in patients with DKD and 11.2% in patients with DCM (p<0.01). Patients with DCM had a longer follow-up than patients with DKD and incidence density rates of overall mortality were calculated. The incidence density rate of overall mortality was 12.9 per 100 patient years in patients with DKD and 11.2 in patients with DCM (p<0.01).
Patients with DKD was associated with higher first year mortality and overall mortality than patients with DCM in univariable analysis (Table 2). The OR for the first year mortality was 1.19 (95% CI: 1.05-1.36, p < 0.01) in patients with DKD. The HR for the overall mortality was 1.21 (95% CI: 1.14-1.28, p < 0.01). The first year mortality was analyzed because the mortality risk was highest in the first year of HD. Male patients were not associated with higher the first year and overall mortality. The number of comorbidity was associated with higher overall mortality but not the first year mortality. Comorbid hypertension, higher hematocrit, higher albumin, higher serum phosphorus, and iPTH were associated with lower first year mortality and overall mortality. Comorbid CAD, comorbid CVA, comorbid liver cirrhosis, higher serum calcium, and higher FBG were associated with higher first year and overall mortality.
In multivariable analysis, the OR of patients DKD was 1.27 (95% CI 1.10-1.47, p < 0.01) for the first year mortality and the HR of patients of DKD was 1.18 (95% CI: 1.12-1.25, p < 0.01) for the overall mortality (Table 3). Patients’ age, comorbid liver cirrhosis, and higher FBG
were associated with higher first year and overall mortality. Every 10 mg/dl higher of FBG was associated with an OR of 1.03 (95% CI: 1.02-1.03) for first year mortality and a HR of 1.02 (95% CI: 1.02-1.03). Higher hematocrit, albumin, and phosphorus were associated with lower first year mortality. The serum phosphorus was used in the multivariable analysis because patients’ serum calcium and serum phosphate were negatively correlated. Every one mg/dl higher of serum phosphorus was associated with an OR of 0.89 (95% CI: 0.85-0.93) for first year mortality and a HR of 0.97 (95% CI: 0.96-0.99) for overall mortality. A higher iPTH was not associated with first year mortality but was associated with lower overall mortality. The HR for every 100 pg/ml higher of iPTH was 0.95 (95% CI: 0.93-0.96).
Discussions
Patients with diabetes as primary kidney disease were associated with a higher first year mortality and overall mortality based on a national registry data of patients on maintenance hemodialysis. This finding was not only found in univariable analysis (Figure 1, Table 2) but also confirmed in multivariable analysis (Table 3). This finding was different from Schroijen
15 et al’s study because a larger number of patients were included and patients’ basal
characteristics were adjusted using propensity score matching in this study. First, the prevalence of patients with DKD was 15% in Schroijens’ study and was 37% in our population. The 37% of prevalence of DKD was close to the reported prevalence of DKD for counties with high prevalence of diabetes in the annual report of USRDS2. Second, patients
on maintenance HD were analyzed in this study but patients on maintenance HD and peritoneal dialysis were included in Schroijens’ study. Third, patients’ baseline characteristics including a higher prevalence of CAD, a higher prevalence of peripheral vascular disease, and older age in DCM patients in Schroijens’ study and these confounders may interact with the effect of DKD on survival. The number of patients they had may not be enough to avoid over adjustments. The poor survival in patients with DKD can be partially explained by higher risk
for cardiovascular disease 22-24, peripheral vascular disease 25, infection 26, and depression 27.
Diabetes as primary kidney disease was usually diagnosed based on normal to relatively large kidneys in renal ultrasound, overt proteinuria in diabetic patients with retinopathy and neuropathy in clinical setting . Renal biopsy was rarely indicated in patients who meet the criteria for the diagnosis of diabetic kidney disease 29. Rigalleaus’ study 14 supported the
hypothesis that patients with diabetes and larger kidneys were associated with poor outcomes. The patients with larger kidneys also had long-standing diabetes suggesting that diabetes may be the primary kidney disease in these patients.
Other comorbidities were important prognostic factors in patients with diabetes and the comorbidities were also analyzed in this study. Patients with comorbid CVA, patients with comorbid CVA, and patients with comorbid liver cirrhosis were independently associated with higher first year mortality and overall mortality in multivariate analysis (Table 3). Glycemic control was one of the most important prognostic factors in diabetic patients 30-33.
Every 10 mg/dl higher of FBG was associated with a 3% higher of first year mortality and a 2% higher of overall mortality. The OR and HR were similar in univariable and multivariable analysis suggesting a strong association between FBG and clinical outcome. Patients with comorbid hypertension was strongly association with lower first year mortality and overall mortality. This may be explained by lower risk of mortality related to intra-dialysis hypotension in patients with comorbid hypertension 34. Higher hematocrit, albumin,
phosphorus, iPTH were independently associated with lower mortality had been widely reported in the previous studies .
There were some potential limitations of this study. First, anti-diabetic and anti-hypertensive medications were not recorded in the registry data. The effect of medications on patients’ survival cannot be analyzed in this study. Second, some of the comorbidity were recorded based on self-reported diagnosis and the prevalence of the comorbidities can be
under-estimated. Third, patients with new onset diabetes diagnosed at the initiation of HD can be missed. This may have limited effect on the result of the study because patients without diabetes were not included in this study. Fourth, the numbers or errors in the registration of variables and the generalization of findings can be limited because of the nature of registry data.
In a large cohort of patients on maintenance hemodialysis, patients with diabetes as primary kidney disease were associated with higher first year mortality and overall mortality, compared to patients with diabetes as comorbidity. This association was independent of the traditional prognostic factors such as hematocrit, albumin, serum phosphorus and other comorbidities including coronary artery disease, cerebral vascular accident, and liver cirrhosis.
Author contributions
HZ Chen, CY Chou: wrote manuscript; CC Liang, HL Kuo: contributed to discussion; CT Chang, JH Liu: analyzed the data; IK Wang: gave critical suggestions to the work; CC Huang: reviewed/edited manuscript.
Acknowledgements
This study was supported by clinical research grants from China Medical University Hospital (DMR-97-035, DMR-98-018, DMR-99-027) and grants from Bureau of Health Promotion, Department of Health (DOH 97-HP-1103).
Conflict of Interest
References
1 Brancati FL, Whelton PK, Randall BL, Neaton JD, Stamler J, Klag MJ. Risk of end-stage renal disease in diabetes mellitus: a prospective cohort study of men screened for MRFIT. Multiple Risk Factor Intervention Trial. JAMA. 1997; 278: 2069-74.
2 New chapter on CKD highlights changes to 15th annual USRDS report. Nephrol News
Issues. 2003; 17: 25-8, 110.
3 Lok CE, Oliver MJ, Rothwell DM, Hux JE. The growing volume of diabetes-related dialysis: a population based study. Nephrol Dial Transplant. 2004; 19: 3098-103.
4 Van Dijk PC, Jager KJ, Stengel B, Gronhagen-Riska C, Feest TG, Briggs JD. Renal replacement therapy for diabetic end-stage renal disease: data from 10 registries in Europe (1991-2000). Kidney Int. 2005; 67: 1489-99.
5 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.
6 Boyle JP, Thompson TJ, Gregg EW, Barker LE, Williamson DF. Projection of the year 2050 burden of diabetes in the US adult population: dynamic modeling of incidence, mortality, and prediabetes prevalence. Popul Health Metr. 2010; 8: 29.
7 Magliano DJ, Soderberg S, Zimmet PZ, Cartensen B, Balkau B, Pauvaday V, et al. Mortality, all-cause and cardiovascular disease, over 15 years in multiethnic mauritius: impact of diabetes and intermediate forms of glucose tolerance. Diabetes Care. 2010; 33: 1983-9.
8 Barr EL, Zimmet PZ, Welborn TA, Jolley D, Magliano DJ, Dunstan DW, et al. Risk of cardiovascular and all-cause mortality in individuals with diabetes mellitus, impaired fasting glucose, and impaired glucose tolerance: the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab). Circulation. 2007; 116: 151-7.
9 K/DOQI clinical practice guidelines for cardiovascular disease in dialysis patients. Am J
Kidney Dis. 2005; 45: S1-153.
10 Report of the expert committee on the diagnosis and classification of diabetes mellitus.
Diabetes Care. 2003; 26 Suppl 1: S5-20.
11 Gaede P, Vedel P, Larsen N, Jensen GV, Parving HH, Pedersen O. Multifactorial intervention and cardiovascular disease in patients with type 2 diabetes. N Engl J Med. 2003; 348: 383-93.
12 Genuth S, Alberti KG, Bennett P, Buse J, Defronzo R, Kahn R, et al. Follow-up report on the diagnosis of diabetes mellitus. Diabetes Care. 2003; 26: 3160-7.
13 Selby JV, FitzSimmons SC, Newman JM, Katz PP, Sepe S, Showstack J. The natural history and epidemiology of diabetic nephropathy. Implications for prevention and control.
JAMA. 1990; 263: 1954-60.
14 Rigalleau V, Garcia M, Lasseur C, Laurent F, Montaudon M, Raffaitin C, et al. Large kidneys predict poor renal outcome in subjects with diabetes and chronic kidney disease.
BMC Nephrol. 2010; 11: 3.
15 MA S, OM D, DC G, M N, JA R, RT K, et al. Survival in dialysis patients is not different between patients with diabetes as primary renal disease and patients with diabetes as a co-morbid condition. BMC Nephrol. 2011; 12: 69.
16 McFarlane SI, McCullough PA, Sowers JR, Soe K, Chen SC, Li S, et al. Comparison of the CKD Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) study equations: prevalence of and risk factors for diabetes mellitus in CKD in the Kidney Early Evaluation Program (KEEP). Am J Kidney Dis. 2011; 57: S24-31.
17 Chou CY, Liang CC, Kuo HL, Chang CT, Liu JH, Lin HH, et al. Comparing risk of new onset diabetes mellitus in chronic kidney disease patients receiving peritoneal dialysis and hemodialysis using propensity score matching. PLoS One. 2014; 9: e87891.
18 Schroijen MA, van de Luijtgaarden MW, Noordzij M, Ravani P, Jarraya F, Collart F, et
al. Survival in dialysis patients is different between patients with diabetes as primary renal
disease and patients with diabetes as a co-morbid condition. Diabetologia. 2013; 56: 1949-57. 19 Dormandy JA, Charbonnel B, Eckland DJ, Erdmann E, Massi-Benedetti M, Moules IK,
et al. Secondary prevention of macrovascular events in patients with type 2 diabetes in the
PROactive Study (PROspective pioglitAzone Clinical Trial In macroVascular Events): a randomised controlled trial. Lancet. 2005; 366: 1279-89.
20 Gottlieb DJ, Punjabi NM, Newman AB, Resnick HE, Redline S, Baldwin CM, et al. Association of sleep time with diabetes mellitus and impaired glucose tolerance. Arch Intern
Med. 2005; 165: 863-7.
21 Lavie P, Herer P, Hoffstein V. Obstructive sleep apnoea syndrome as a risk factor for hypertension: population study. BMJ. 2000; 320: 479-82.
22 Wei M, Gaskill SP, Haffner SM, Stern MP. Effects of diabetes and level of glycemia on all-cause and cardiovascular mortality. The San Antonio Heart Study. Diabetes Care. 1998; 21: 1167-72.
23 Glucose tolerance and cardiovascular mortality: comparison of fasting and 2-hour diagnostic criteria. Arch Intern Med. 2001; 161: 397-405.
24 Villar E, Chang SH, McDonald SP. Incidences, treatments, outcomes, and sex effect on survival in patients with end-stage renal disease by diabetes status in Australia and New Zealand (1991 2005). Diabetes Care. 2007; 30: 3070-6.
25 Belch J, MacCuish A, Campbell I, Cobbe S, Taylor R, Prescott R, et al. The prevention of progression of arterial disease and diabetes (POPADAD) trial: factorial randomised placebo controlled trial of aspirin and antioxidants in patients with diabetes and asymptomatic peripheral arterial disease. BMJ. 2008; 337: a1840.
26 Dalrymple LS, Johansen KL, Chertow GM, Cheng SC, Grimes B, Gold EB, et al. Infection-related hospitalizations in older patients with ESRD. Am J Kidney Dis. 2010; 56: 522-30.
27 Lin EH, Rutter CM, Katon W, Heckbert SR, Ciechanowski P, Oliver MM, et al. Depression and advanced complications of diabetes: a prospective cohort study. Diabetes
Care. 2010; 33: 264-9.
28 Levey AS, Coresh J, Balk E, Kausz AT, Levin A, Steffes MW, et al. National Kidney Foundation practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Ann Intern Med. 2003; 139: 137-47.
29 Walker PD, Cavallo T, Bonsib SM. Practice guidelines for the renal biopsy. Mod Pathol. 2004; 17: 1555-63.
30 Williams ME, Lacson E, Jr., Teng M, Ofsthun N, Lazarus JM. Hemodialyzed type I and type II diabetic patients in the US: Characteristics, glycemic control, and survival. Kidney Int. 2006; 70: 1503-9.
31 Snit M, Dwornicki M, Zukowska-Szczechowska E, Grzeszczak W. Impact of glycemic control on survival of diabetic patients on chronic regular hemodialysis: a 7-year observational study. Diabetes Care. 2007; 30: 189; author reply 89-90.
32 Cefalu WT, Watson K. Intensive glycemic control and cardiovascular disease observations from the ACCORD study: now what can a clinician possibly think? Diabetes. 2008; 57: 1163-5.
33 Ishimura E, Okuno S, Kono K, Fujino-Kato Y, Maeno Y, Kagitani S, et al. Glycemic control and survival of diabetic hemodialysis patients--importance of lower hemoglobin A1C levels. Diabetes Res Clin Pract. 2009; 83: 320-6.
34 Zager PG, Nikolic J, Brown RH, Campbell MA, Hunt WC, Peterson D, et al. "U" curve association of blood pressure and mortality in hemodialysis patients. Medical Directors of Dialysis Clinic, Inc. Kidney Int. 1998; 54: 561-9.
Legends
Figure 1. Scheme of study design
Figure 2. Survival curve of patients with diabetes as primary kidney disease (DKD) and patients with diabetes as comorbidity (DCM)
Table 1. Clinical characteristics of all patients DKD n=13160 DCM n=2632 p Age 61.4±10.8 61.7±11.7 0.30 Male n(%) 6551(49.8) 1314(49.9) 0.89 Follow-up (year) 4.5(3.1-6.6) 4.9(3.3-7.6) <0.01
Primary kidney disease
Diabetes 13160(100) 0(0) -CGN 0(0) 1235(46.9) -Hypertension 0(0) 270(10.3) -Number of comorbidity 2.0±1.0 2.0±1.0 0.99 Comorbidity Hypertension 7185(54.6) 1436(54.6) 0.99 CAD 2379(18.1) 474(18.0) 0.93 CVA 1026(7.8) 192(7.3) 0.37 Liver cirrhosis 840(6.4) 168(6.4) 0.99 Cancer 395(3) 79(3) 0.99 Hematocrit 29.4±3.5 29.3±3.6 0.17 Albumin (g/dl) 3.7±0.4 3.7±0.4 0.99 Calcium (mg/dl) 9.6±0.8 9.6±0.8 0.64 Phosphorus (mg/dl) 4.7±1.3 4.7±1.3 0.82 FBG (mg/dl) 192±87 169±83 <0.01 iPTH (pg/ml) 78.5(35-164) 89.9(40.9-185.1) <0.01*
DKD: patients with diabetic as primary kidney disease, DCM: patients with diabetes as comorbidity, CGN, chronic glomerulonephritis; CAD: coronary artery disease, CVA: cerebral vascular accident, FBG, fasting blood glucose; iPTH, intact parathyroid hormone.
Table 2. Odds ratio (OR) of possible confounders for the first year mortality and hazard ratio (HR) of possible confounders for overall mortality in univariable analysis
Possible confounders OR (95% CI) of first year mortality
HR (95% CI) of overall mortality
DKD v.s. DCM 1.19 (1.05-1.36) 1.21 (1.14-1.28)
Age (every 10 additional years) 1.56 (1.49-1.63) 1.47 (1.44-1.50)
Male 0.99 (0.90-1.08) 1.02 (0.98-1.06)
Number of comorbidity (every one more) 1.04 (0.99-1.09) 1.03 (1.01-1.05) Hypertension 0.78 (0.72-0.86) 0.88 (0.85-0.92) CAD 1.16 (1.04-1.30) 1.15 (1.10-1.21) CVA 1.25 (1.07-1.47) 1.24 (1.16-1.33) Liver cirrhosis 1.23 (1.04-1.45) 1.09 (1.02-1.17) Cancer 1.28 (0.98-1.68) 1.17 (1.04-1.32)
Hematocrit (ever 1 % higher) 0.89 (0.88-0.90) 0.94 (0.93-0.94) Albumin (every 1g/dl higher) 0.17 (0.15-0.19) 0.33 (0.32-0.35) Calcium (every 1 mg/dl higher) 1.09 (1.03-1.15) 1.05 (1.03-1.08) Phosphorus (every 1 mg/dl higher) 0.78 (0.75-0.81) 0.86 (0.84-0.87) FBG (every 10 mg/dl higher) 1.03 (1.02-1.03) 1.02 (1.02-1.02) iPTH (every 100pg/ml higher) 0.90 (0.87-0.94) 0.89 (0.88-0.91) DKD: patients with diabetic as primary kidney disease, DCM: patients with diabetes as comorbidity, CGN, chronic glomerulonephritis; CAD: coronary artery disease, CVA: cerebral vascular accident, FBG, fasting blood glucose; iPTH, intact parathyroid hormone.
Table 3. Odds ratio (OR) of possible confounders for the first year mortality and hazard ratio (HR) of possible confounders for overall mortality in multivariable analysis
Possible confounders OR (95% CI) of first year mortality
HR (95% CI) of overall mortality
DKD v.s. DCM 1.27 (1.10-1.47) 1.18 (1.12-1.25)
Age (every 10 additional years) 1.51 (1.43-1.59) 1.46 (1.43-1.49)
Hypertension 0.79 (0.71-0.87) 0.88 (0.85-0.92)
CAD 1.08 (0.94-1.23) 1.11 (1.06-1.17)
CVA 1.03 (0.86-1.25) 1.08 (1.01-1.16)
Liver cirrhosis 1.34 (1.12-1.61) 1.14 (1.06-1.22)
Hematocrit (ever 1 % higher) 0.91 (0.89-0.92) 0.94 (0.94-0.95) Albumin (every 1g/dl higher) 0.23 (0.21-0.27) 0.45 (0.43-0.48) Phosphorus (every 1 mg/dl higher) 0.89 (0.85-0.93) 0.97 (0.96-0.99) FBG (every 10 mg/dl higher) 1.03 (1.02-1.03) 1.02 (1.02-1.03) iPTH (every 100pg/ml higher) 0.97 (0.93-1.05) 0.95 (0.93-0.96) DKD: diabetes as primary kidney disease, DCM: diabetes as comorbidity, CAD: coronary artery disease, CVA: cerebral vascular accident, FBG: fasting blood glucose, iPTH: intact parathyroid hormone
Figure 2. Survival curve of patients with diabetes as primary kidney disease (DKD) and patients with diabetes as comorbidity (DCM)
0 .0 0 0 .2 5 0 .5 0 0 .7 5 1 .0 0 2632 1270 290 0 DCMDKD13160 5487 755 0 Number at risk 0 5 10 15 Year DKD DCM
