Original Paper Received: March 1, 2015 Accepted: September 20, 2015 Published online: November 26, 2015
Neuroepidemiology 2016;46:24–30 DOI: 10.1159/000441281
Chronic Kidney Disease and Functional Outcomes 6 Months after Ischemic Stroke: A Prospective Multicenter Study Shin Yi Jang a Min Kyun Sohn l Jongmin Lee d Deog Young Kim e Sam-Gyu Lee h Yong-Il Shin g Gyung-Jae Oh i Yang-Soo Lee f Min Cheol Joo j Eun Young Han k Won Hyuk Chang b Ahee Lee b, c Jeong Hyun Kim b, c Yun-Hee Kim a–c
a Heart Vascular Stroke Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, b Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, c Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, d Department of Rehabilitation Medicine, Konkuk University School of Medicine, e Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, f Department of Rehabilitation Medicine, Kyung-pook National University College of Medicine, Daegu, g Department of Rehabilitation Medicine, Pusan National University School of Medicine, Busan, h Department of Physical and Rehabilitation Medicine, Chonnam National University Medical School, Kwangju, i Department of Public Health and Preventive Medicine, Wonkwang University, College of Medicine, j Department of Rehabilitation Medicine, Wonkwang University School of Medicine, Iksan, k Department of Rehabilitation Medicine, Jeju University Hospital, University of Jeju College of Medicine, Jeju, and l Department of Rehabilitation Medicine, School of Medicine, Chungnam National University, Daejeon, Republic of Korea
Abstract Background: The aim of this study was to investigate whether chronic kidney disease (CKD) predicts the outcome of the Functional Independence Measure (FIM) and the Korean version of the modified Barthel Index (K-MBI) 6 months after stroke with adjustment for age, gender, education, smoking, drinking, obesity, hypertension, diabetes mellitus, dyslipidemia, the FIM or K-MBI at discharge and the National Institutes of Health Stroke Scale (NIHSS) score 7 days post stroke. Methods: This study is an interim report of the Korean Stroke
© 2015 S. Karger AG, Basel 0251–5350/15/0461–0024$39.50/0 E-Mail [email protected] www.karger.com/ned
Cohort for Functioning and Rehabilitation. The sample included 2,037 ischemic stroke patients aged 18 years or older. The FIM and K-MBI scores were assessed at discharge and at 6 months after the onset of stroke. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. CKD was defined as an eGFR 200 mg/dl or low density lipoprotein >130 mg/dl. Obesity was based on body mass index (BMI) and was defined as BMI ≥25 [6].
The mean age was 65.5 (±12.4) years. The proportion of patients older than 65 years was 55.0%. The proportion of men was 62.6%. The proportion of stroke risk factors was the following: over 80% had HT, over 50% had DM, over 35% had dyslipidemia or were obese, approximately 30% were current smokers and over 10% had CKD. The proportion of patients who were current drinkers was approximately 30%; the proportion of patients who had an elementary education was approximately 30%. Generally, lower FIM and K-MBI scores at 6 months were observed in patients who were older, were female, had lower education, had HT, had DM or had CKD. Additionally, patients who were non-smokers, non-drinkers and not obese had lower FIM and K-MBI scores at 6 months (table 1). In a multiple linear regression, the 6-month FIM after stroke was significantly associated with CKD (–2.85, p < 0.05), age (–0.29, p < 0.01), the FIM at discharge (0.46, p < 0.01) and the 7-day NIHSS score (–1.71, p < 0.01) after adjusting for confounding variables. The post-stroke KMBI at 6 months was significantly associated with CKD (–2.88, p < 0.01), age (–0.27, p < 0.01), the K-MBI at discharge (0.46, p < 0.01) and the 7-day NIHSS score (–1.55, p < 0.01) after adjusting for confounding variables (table 2).
Statistical Analyses Distribution of general characteristics, clinical data, covariate variables and functional outcome factors were analyzed as the mean (±SD) or median (interquartile range) for continuous variables and percentage for categorical variables. Student’s t test or 1-way analysis of variance was used for continuous variables and χ2 test for categorical variables. Multiple linear regression analyses
26
Neuroepidemiology 2016;46:24–30 DOI: 10.1159/000441281
Discussion
In our study, overall, CKD appears to be an independent predictor of a poor FIM and K-MBI scores at 6 months after a stroke after adjusting for confounding variables, which is in line with previous studies [15, 16]. An additional analysis in this study shows that CKD was significantly associated with poor FIM and K-MBI outcomes at 3 months (online suppl. table 1; for all online suppl. material, see www.karger.com/ doi/10.1159/000441281). These findings were agreed with a plethora of empirical studies with mRS [5, 17] and the Barthel Index [18, 19] at 3 months. Stroke patients with CKD had worse functional outcomes than without CKD [2]. However, there are significant discrepancies beJang et al.
Downloaded by: Weizmann Inst. of Science 198.143.58.1 - 1/21/2016 2:09:58 PM
Covariate Variables Education was classified into 3 categories: (1) elementary school: elementary school or 6 years or less of schooling, (2) middle/high school: middle school or 7–12 years of schooling and (3) college, university: college or >12 years of schooling. A subject was identified as a current smoker if he/she had smoked within 1 year of the survey date. A subject was defined as a current drinker if he/ she had consumed an alcoholic drink within 1 year of the survey date.
Results
Table 1. Distribution of FIM and K-MBI scores at 6 months after stroke according to general characteristics, stroke risk factor and co-
variates (n = 2,037) Variables Overall Age, years 18–44 45–64 65 Gender Male Female Education College Middle or high school Elementary or under Smoking Never Former Current Drinking, current Non Current BMI Non-obese Obese HT No Yes DM No Yes Dyslipidemia No Yes CKD No Yes Renal disease No Yes Systolic blood pressure, mm Hg Diastolic blood pressure, mm Hg Fasting blood sugar, mg/dl Total cholesterol, mg/dl Triglyceride, mg/dl High density lipoprotein, mg/dl Low density lipoprotein, mg/dl Cr, mg/dl eGFR, ml/min/1.73 m2 FIM, discharge FIM, 3 months K-MBI, discharge K-MBI, 3 months NIHSS, 7 days, mean ± SD Median (IQR)
All
FIM, 6 months
p value*
K-MBI, 6 months
p value*
– 65.5±12.4 6.1 38.9 55.0
109.8±27.9
–
Neuroepidemiology 2016;46:24–30 DOI: 10.1159/000441281
Chronic Kidney Disease and Functional Outcomes 6 Months after Ischemic Stroke: A Prospective Multicenter Study Shin Yi Jang a Min Kyun Sohn l Jongmin Lee d Deog Young Kim e Sam-Gyu Lee h Yong-Il Shin g Gyung-Jae Oh i Yang-Soo Lee f Min Cheol Joo j Eun Young Han k Won Hyuk Chang b Ahee Lee b, c Jeong Hyun Kim b, c Yun-Hee Kim a–c
a Heart Vascular Stroke Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, b Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, c Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, d Department of Rehabilitation Medicine, Konkuk University School of Medicine, e Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, f Department of Rehabilitation Medicine, Kyung-pook National University College of Medicine, Daegu, g Department of Rehabilitation Medicine, Pusan National University School of Medicine, Busan, h Department of Physical and Rehabilitation Medicine, Chonnam National University Medical School, Kwangju, i Department of Public Health and Preventive Medicine, Wonkwang University, College of Medicine, j Department of Rehabilitation Medicine, Wonkwang University School of Medicine, Iksan, k Department of Rehabilitation Medicine, Jeju University Hospital, University of Jeju College of Medicine, Jeju, and l Department of Rehabilitation Medicine, School of Medicine, Chungnam National University, Daejeon, Republic of Korea
Abstract Background: The aim of this study was to investigate whether chronic kidney disease (CKD) predicts the outcome of the Functional Independence Measure (FIM) and the Korean version of the modified Barthel Index (K-MBI) 6 months after stroke with adjustment for age, gender, education, smoking, drinking, obesity, hypertension, diabetes mellitus, dyslipidemia, the FIM or K-MBI at discharge and the National Institutes of Health Stroke Scale (NIHSS) score 7 days post stroke. Methods: This study is an interim report of the Korean Stroke
© 2015 S. Karger AG, Basel 0251–5350/15/0461–0024$39.50/0 E-Mail [email protected] www.karger.com/ned
Cohort for Functioning and Rehabilitation. The sample included 2,037 ischemic stroke patients aged 18 years or older. The FIM and K-MBI scores were assessed at discharge and at 6 months after the onset of stroke. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. CKD was defined as an eGFR 200 mg/dl or low density lipoprotein >130 mg/dl. Obesity was based on body mass index (BMI) and was defined as BMI ≥25 [6].
The mean age was 65.5 (±12.4) years. The proportion of patients older than 65 years was 55.0%. The proportion of men was 62.6%. The proportion of stroke risk factors was the following: over 80% had HT, over 50% had DM, over 35% had dyslipidemia or were obese, approximately 30% were current smokers and over 10% had CKD. The proportion of patients who were current drinkers was approximately 30%; the proportion of patients who had an elementary education was approximately 30%. Generally, lower FIM and K-MBI scores at 6 months were observed in patients who were older, were female, had lower education, had HT, had DM or had CKD. Additionally, patients who were non-smokers, non-drinkers and not obese had lower FIM and K-MBI scores at 6 months (table 1). In a multiple linear regression, the 6-month FIM after stroke was significantly associated with CKD (–2.85, p < 0.05), age (–0.29, p < 0.01), the FIM at discharge (0.46, p < 0.01) and the 7-day NIHSS score (–1.71, p < 0.01) after adjusting for confounding variables. The post-stroke KMBI at 6 months was significantly associated with CKD (–2.88, p < 0.01), age (–0.27, p < 0.01), the K-MBI at discharge (0.46, p < 0.01) and the 7-day NIHSS score (–1.55, p < 0.01) after adjusting for confounding variables (table 2).
Statistical Analyses Distribution of general characteristics, clinical data, covariate variables and functional outcome factors were analyzed as the mean (±SD) or median (interquartile range) for continuous variables and percentage for categorical variables. Student’s t test or 1-way analysis of variance was used for continuous variables and χ2 test for categorical variables. Multiple linear regression analyses
26
Neuroepidemiology 2016;46:24–30 DOI: 10.1159/000441281
Discussion
In our study, overall, CKD appears to be an independent predictor of a poor FIM and K-MBI scores at 6 months after a stroke after adjusting for confounding variables, which is in line with previous studies [15, 16]. An additional analysis in this study shows that CKD was significantly associated with poor FIM and K-MBI outcomes at 3 months (online suppl. table 1; for all online suppl. material, see www.karger.com/ doi/10.1159/000441281). These findings were agreed with a plethora of empirical studies with mRS [5, 17] and the Barthel Index [18, 19] at 3 months. Stroke patients with CKD had worse functional outcomes than without CKD [2]. However, there are significant discrepancies beJang et al.
Downloaded by: Weizmann Inst. of Science 198.143.58.1 - 1/21/2016 2:09:58 PM
Covariate Variables Education was classified into 3 categories: (1) elementary school: elementary school or 6 years or less of schooling, (2) middle/high school: middle school or 7–12 years of schooling and (3) college, university: college or >12 years of schooling. A subject was identified as a current smoker if he/she had smoked within 1 year of the survey date. A subject was defined as a current drinker if he/ she had consumed an alcoholic drink within 1 year of the survey date.
Results
Table 1. Distribution of FIM and K-MBI scores at 6 months after stroke according to general characteristics, stroke risk factor and co-
variates (n = 2,037) Variables Overall Age, years 18–44 45–64 65 Gender Male Female Education College Middle or high school Elementary or under Smoking Never Former Current Drinking, current Non Current BMI Non-obese Obese HT No Yes DM No Yes Dyslipidemia No Yes CKD No Yes Renal disease No Yes Systolic blood pressure, mm Hg Diastolic blood pressure, mm Hg Fasting blood sugar, mg/dl Total cholesterol, mg/dl Triglyceride, mg/dl High density lipoprotein, mg/dl Low density lipoprotein, mg/dl Cr, mg/dl eGFR, ml/min/1.73 m2 FIM, discharge FIM, 3 months K-MBI, discharge K-MBI, 3 months NIHSS, 7 days, mean ± SD Median (IQR)
All
FIM, 6 months
p value*
K-MBI, 6 months
p value*
– 65.5±12.4 6.1 38.9 55.0
109.8±27.9
–
