Economic Impact of Donating a Kidney on Living Donors: A Korean Cohort Study.

RATIONALE & OBJECTIVE: Although existing studies have reported adverse health outcomes after kidney donation, its socioeconomic impact on living donors requires further study. STUDY DESIGN: A retrospective observational cohort study including a matched comparison group. SETTING & PARTICIPANTS: 1,285 living kidney donors from 7 tertiary hospitals between 2003 and 2016, and a matched comparison group consisting of the same number of health screening examinees with similar baseline clinical characteristics and socioeconomic status. All participants were receiving Korean national health insurance. EXPOSURE: Kidney donation as reflected in the Korean National Health Insurance System (NHIS) database. OUTCOME: Changes in household economic status estimated by Korean national health insurance fees and changes in employment status reflected in the NHIS database. ANALYTICAL APPROACH: The outcomes of the donor group and matched control group were compared annually using multivariable logistic regression analyses adjusted for clinical and demographic characteristics. RESULTS: The median ages of the donors and matched controls were 45 and 46 years, respectively; 44.6% of both groups were male. Compared to the comparison group, living donors were at higher risk of being unemployed or losing employment during the first 2 years after donation (eg, first-year loss of employment: odds ratio (OR), 2.27 [95% CI, 1.55-3.33]); however, this association did not persist. Donors also had a significantly lower odds of improvement in economic status (OR, 0.57 [95% CI, 0.47-0.71]) and a higher odds of deterioration in financial status (OR, 1.54 [95% CI, 1.23-1.93]) in the first year after transplantation and subsequently. LIMITATIONS: Unmeasured differences between donors and matched controls creating residual selection bias and confounding. CONCLUSIONS: Living kidney donors may suffer loss of employment and poor economic status after their voluntary donation. The socioeconomic impact on these donors should be considered in conjunction with the potential long-term adverse health outcomes after donation.

Causal linkage between adult height and kidney function: An integrated population-scale observational analysis and Mendelian randomization study.

As adult height is linked to various health outcomes, further investigation of its causal effects on kidney function later in life is warranted. This study involved a cross-sectional observational analysis and summary-level Mendelian randomization (MR) analysis. First, the observational association between height and estimated GFR determined by creatinine (eGFRcreatinine) or cystatin C (eGFRcystatinC) was investigated in 467,182 individuals aged 40-69 using UK Biobank. Second, the genetic instrument for adult height, as reported by the GIANT consortium, was implemented, and summary-level MR of eGFRcreatinine and CKDcreatinine in a CKDGen genome-wide association study was performed (N = 567,460), with multivariable MR being adjusted for the effects of genetic predisposition on body mass index. To replicate the findings, additional two-sample MR using the summary statistics of eGFRcystatinC and CKDcystatinC in UK Biobank was performed (N = 321,405). In observational analysis, adult height was inversely associated with both eGFRcreatinine (per 1 SD, adjusted beta -1.039, standard error 0.129, P < 0.001) and eGFRcystatinC (adjusted beta -1.769, standard error 0.161, P < 0.001) in a multivariable model adjusted for clinicodemographic, anthropometric, metabolic, and social factors. Moreover, multivariable summary-level MR showed that a taller genetically predicted adult height was causally linked to a lower log-eGFRcreatinine (adjusted beta -0.007, standard error 0.001, P < 0.001) and a higher risk of CKDcreatinine (adjusted beta 0.083, standard error 0.019, P < 0.001). Other pleiotropy-robust sensitivity MR analysis results supported the findings. In addition, similar results were obtained by two-sample MR of eGFRcystatinC (adjusted beta -1.303, standard error 0.140, P < 0.001) and CKDcystatinC (adjusted beta 0.153, standard error 0.025, P < 0.001) in UK Biobank. In conclusion, the results of this study suggest that a taller adult height is causally linked to worse kidney function in middle-aged to elderly individuals, independent of the effect of body mass index.

Pharmacist-Led Collaborative Medication Management for the Elderly with Chronic Kidney Disease and Polypharmacy.

Inappropriate polypharmacy is likely in older adults with chronic kidney disease (CKD) owing to the considerable burden of comorbidities. We aimed to describe the impact of pharmacist-led geriatric medication management service (MMS) on the quality of medication use. This retrospective descriptive study included 95 patients who received geriatric MMS in an ambulatory care clinic in a single tertiary-care teaching hospital from May 2019 to December 2019. The average age of the patients was 74.9 ± 7.3 years; 40% of them had CKD Stage 4 or 5. Medication use quality was assessed in 87 patients. After providing MMS, the total number of medications and potentially inappropriate medications (PIMs) decreased from 13.5 ± 4.3 to 10.9 ± 3.8 and 1.6 ± 1.4 to 1.0 ± 1.2 (both p < 0.001), respectively. Furthermore, the number of patients who received three or more central nervous system-active drugs and strong anticholinergic drugs decreased. Among the 354 drug-related problems identified, "missing patient documentation" was the most common, followed by "adverse effect" and "drug not indicated." The most frequent intervention was "therapy stopped". In conclusion, polypharmacy and PIMs were prevalent in older adults with CKD; pharmacist-led geriatric MMS improved the quality of medication use in this population.

Disparity in Accessibility to and Prognosis of Kidney Transplantation According to Economic Inequality in South Korea: A Widening Gap After Expansion of Insurance Coverage.

BACKGROUND: Nationwide studies on the effects of wealth inequality on kidney transplantation are rare, particularly in a country with an expanded National Health Insurance Service and in Asian countries. METHODS: In this nationwide, population-based cohort study, we reviewed the national claims database of Korea in which details of nationwide health insurance are provided. From 2007 to 2015, 9 annual cohorts of end-stage renal disease patients were included. The annual financial statuses were collected and stratified into 5 subgroups in each year: the aided group in which insurance fee was waived and the 4 other groups divided by quartiles of their medical insurance fee. Time trends of incidence proportion of kidney transplantation among end-stage renal disease patients in each year were initially assessed. The risk of graft failure, both including death-censored graft failure and death with a functioning graft, was analyzed as a prognostic outcome within the transplant recipients. RESULTS: Significant disparity in the accessibility of kidney transplantation was present, and it was further widening, particularly from 2009 in which the National Health Insurance Service started to cover desensitized kidney transplantation. Desensitized or preemptive transplantation was less common in the poorest group who were more frequently receiving transplantation after 5 years of dialysis in the latter years. The prognosis of kidney transplantation was significantly worse in the poorer people, and this disparity also worsened during the study period. CONCLUSIONS: Prominent disparity regarding accessibility to and prognosis of kidney transplantation was observed in Korea according to wealth inequality, and this disparity was worsening.

Socioeconomic dependency and kidney transplantation accessibility and outcomes: a nationwide observational cohort study in South Korea.

BACKGROUND: Socioeconomic status is an important determinant for patients' accessibility to, and prognosis of, kidney transplantation. However, the association between socioeconomic dependency and kidney transplantation accessibility or prognosis after kidney transplantation remains unclear. METHODS: In this nationwide cohort study, based on the claims database of South Korea, we included 12,889 kidney transplant recipients from 2007 to 2015 and stratified them according to health insurance categories that reflect socioeconomic dependency: workplace-independent (employed, N = 3257), workplace-dependent (dependent to the workplace-independent, N = 3661), community-representative (heads of the household but self-employed or unemployed, N = 2479), community-member (N = 1618), aided-representative (heads of household receiving medical aid from the government, N = 1580), and aided-member (N = 294). The incidence of kidney transplantation was calculated to evaluate its accessibility. The risk of graft failure was assessed using the Cox regression analysis, adjusted for clinicodemographic variables, including financial status. RESULTS: End-stage kidney disease patients who were employed (workplace-independent group) had the highest incidence proportion of kidney transplantation. The dependent groups' prognoses were worse than those of their independent counterparts [workplace-dependent versus workplace-independent, HR 1.26 (1.11-1.43) and community-dependent versus community-independent, HR 1.46 (1.23-1.74)], although no difference was observed between the aided subgroups [aided-dependent versus aided-independent, adjusted HR 1.16 (0.90-1.50)]. CONCLUSION: Disparities in kidney transplantation accessibility were present in South Korea according to socioeconomic dependency; these differences may have an impact on prognosis.

Can a semi-quantitative method replace the current quantitative method for the annual screening of microalbuminuria in patients with diabetes? Diagnostic accuracy and cost-saving analysis considering the potential health burden.

OBJECTIVES: Diabetes is a global epidemic, and the high cost of annually and quantitatively measuring urine albumin excretion using the turbidimetric immunoassay is challenging. We aimed to determine whether a semi-quantitative urinary albumin-creatinine ratio test could be used as a screening tool for microalbuminuria in diabetic patients. METHODS: We assessed the diagnostic accuracy of the semi-quantitative method. The costs of false results in the semi-quantitative method were calculated based on the annual probability of disease progression analyzed through a systematic literature review and meta-analysis. The pooled long-term cost-saving effect of the semi-quantitative method compared with the quantitative test was assessed using a Markov model simulating a long-term clinical setting. Diagnostic accuracy and the cost-saving effect were also validated in an independent external cohort. RESULTS: Compared with the quantitative test, the semi-quantitative method had sensitivities of 93.5% and 81.3% and specificities of 61.4% and 63.1% in the overall sample of diabetic patients (n = 1,881) and in diabetic patients with eGFR ≥60 ml/min/1.73 m2 and a negative dipstick test (n = 1,110), respectively. After adjusting for direct and indirect medical costs, including the risk of disease progression, which was adjusted by the meta-analyzed hazard ratio for clinical outcomes, it was determined that using the semi-quantitative method could save 439.4 USD per person for 10 years. Even after adjusting the result to the external validation cohort, 339.6 USD could be saved for one diabetic patient for 10 years. CONCLUSIONS: The semi-quantitative method could be an appropriate screening tool for albuminuria in diabetic patients. Moreover, it can minimize the testing time and inconvenience and significantly reduce national health costs.

Assessment of Hepatic Cytochrome P450 3A Activity Using Metabolic Markers in Patients with Renal Impairment.

BACKGROUND: The renal function of individuals is one of the reasons for the variations in therapeutic response to various drugs. Patients with renal impairment are often exposed to drug toxicity, even with drugs that are usually eliminated by hepatic metabolism. Previous study has reported an increased plasma concentration of indoxyl sulfate and decreased plasma concentration of 4ß-hydroxy (OH)-cholesterol in stable kidney transplant recipients, implicating indoxyl sulfate as a cytochrome P450 (CYP) inhibiting factor. In this study, we aimed to evaluate the impact of renal impairment severity-dependent accumulation of indoxyl sulfate on hepatic CYP3A activity using metabolic markers. METHODS: Sixty-six subjects were enrolled in this study; based on estimated glomerular filtration rate (eGFR), they were classified as having mild, moderate, or severe renal impairment. The plasma concentration of indoxyl sulfate was quantified using liquid chromatography-mass spectrometry (LC-MS). Urinary and plasma markers (6ß-OH-cortisol/cortisol, 6ß-OH-cortisone/cortisone, 4ß-OH-cholesterol) for hepatic CYP3A activity were quantified using gas chromatography-mass spectrometry (GC-MS). The total plasma concentration of cholesterol was measured using the enzymatic colorimetric assay to calculate the 4ß-OH-cholesterol/cholesterol ratio. The correlation between variables was assessed using Pearson's correlation test. RESULTS: There was a significant negative correlation between MDRD eGFR and indoxyl sulfate levels. The levels of urinary 6ß-OH-cortisol/cortisol and 6ß-OH-cortisone/cortisone as well as plasma 4ß-OH-cholesterol and 4ß-OH-cholesterol/cholesterol were not correlated with MDRD eGFR and the plasma concentration of indoxyl sulfate. CONCLUSION: Hepatic CYP3A activity may not be affected by renal impairment-induced accumulation of plasma indoxyl sulfate.

The association of moderate renal dysfunction with impaired preference-based health-related quality of life: third Korean national health and nutritional examination survey.

BACKGROUND: Only a few large-scale studies have investigated the association between health-related quality of life (HRQOL) and renal function. Moreover, the HRQOL of patients with moderate renal dysfunction is frequently underestimated by healthcare providers. This study assessed the impact of renal function on preference-based HRQOL in Korean adult population. METHODS: We analyzed data for 5,555 adults from the 3(rd) Korean National Health and Nutritional Examination Survey 2005. The EuroQol-5D (EQ-5D) utility score was used to evaluate HRQOL. The study subjects were stratified into three groups based on their estimated glomerular filtration rates (eGFRs): ≥ 90.0, 60.0-89.9 and 30.0-59.9 mL/min/1.73 m(2). Individuals with advanced renal dysfunction were excluded from the analysis. RESULTS: The proportions of participants who reported problems in each of the five EQ-5D dimensions increased significantly with decreasing eGFR. However, a significant decrease in the EQ-5D utility score was observed among participants with an eGFR of 30.0-59.9 mL/min/1.73 m(2). Participants with an eGFR of 30.0-59.9 mL/min/1.73 m(2) had an almost 1.5-fold higher risk of impaired health utility (the lowest quartile of EQ-5D utility score) compared with those participants with eGFRs ≥ 90.0 mL/min/1.73 m(2), after adjustment for age, gender, health-related behaviors, socioeconomic and psychological variables, and other comorbidities. Among the five dimensions of the EQ-5D, an eGFR of 30.0-59.9 mL/min/1.73 m(2) was an independent determinant of self-reported problems in the mobility and pain/discomfort dimensions. CONCLUSIONS: Although age affects the association between renal dysfunction and the EQ-5D, moderate renal dysfunction seems to be an important determinant of impaired health utility in a general population and may affect the mobility and pain/discomfort dimensions of health utility.

A threshold value of estimated glomerular filtration rate that predicts changes in serum 25-hydroxyvitamin D levels: 4th Korean National Health and Nutritional Examination Survey 2008.

BACKGROUND: Vitamin D deficiency is known as an important risk factor for mortality in patients with chronic kidney disease (CKD). Nevertheless, the association of renal function itself with vitamin D status or serum 25-hydroxyvitamin D (25OHD) level has not been investigated thoroughly. METHODS: We examined the association between the estimated glomerular filtration rate (eGFR) and serum 25OHD levels using data from the 4th Korean National Health and Nutritional Examination Survey 2008. Generalized additive models (GAMs) were used to examine the relationship between eGFR and serum 25OHD levels and to estimate a threshold value of eGFR that predicts changes in serum 25OHD levels. RESULTS: The mean serum 25OHD level was 20.4 ± 9.1 ng/mL, and the overall prevalence of vitamin D deficiency was 29.9% in this population. The prevalence of vitamin D deficiency began to increase at eGFR levels <45 mL/min/1.73 m(2). After adjustment, the logistic regression of dichotomized eGFR levels with a cut-point of 45 mL/min/1.73 m(2) yielded an increased odds ratio for vitamin D deficiency. Additionally, the continuous relationship between eGFR and 25OHD levels was explored using GAMs adjusted for various confounding factors. In this analysis, the difference from the mean serum 25OHD started to increase below an eGFR threshold of 55.4 mL/min/1.73 m(2), which suggests that renal function is directly related to the serum 25OHD levels in patients with CKD Stages 3-5. CONCLUSION: Although moderate renal dysfunction (eGFR < 45 mL/min/1.73 m(2)) is an important predictor of vitamin D deficiency, serum 25OHD levels start to decrease below an eGFR level of ~60 mL/min/1.73 m(2) independent of other risk factors. These results suggest that more careful attention to 25OHD levels may be needed when patients reach Stage 3 CKD.