Dietary protein intake and kidney function decline after myocardial infarction: the Alpha Omega Cohort.

BACKGROUND: Post-myocardial infarction (MI) patients have a doubled rate of kidney function decline compared with the general population. We investigated the extent to which high intake of total, animal and plant protein are risk factors for accelerated kidney function decline in older stable post-MI patients. METHODS: We analysed 2255 post-MI patients (aged 60-80 years, 80% men) of the Alpha Omega Cohort. Dietary data were collected with a biomarker-validated 203-item food frequency questionnaire. At baseline and 41 months, we estimated glomerular filtration rate based on the Chronic Kidney Disease Epidemiology Collaboration equations for serum cystatin C [estimated glomerular filtration rate (eGFRcysC)] alone and both creatinine and cystatin C (eGFRcr-cysC). RESULTS: Mean [standard deviation (SD)] baseline eGFRcysC and eGFRcr-cysC were 82 (20) and 79 (19) mL/min/1.73 m2. Of all patients, 16% were current smokers and 19% had diabetes. Mean (SD) total protein intake was 71 (19) g/day, of which two-thirds was animal and one-third plant protein. After multivariable adjustment, including age, sex, total energy intake, smoking, diabetes, systolic blood pressure, renin-angiotensin system blocking drugs and fat intake, each incremental total daily protein intake of 0.1 g/kg ideal body weight was associated with an additional annual eGFRcysC decline of -0.12 (95% confidence interval -0.19 to -0.04) mL/min/1.73 m2, and was similar for animal and plant protein. Patients with a daily total protein intake of ≥1.20 compared with <0.80 g/kg ideal body weight had a 2-fold faster annual eGFRcysC decline of -1.60 versus -0.84 mL/min/1.73 m2. Taking eGFRcr-cysC as outcome showed similar results. Strong linear associations were confirmed by restricted cubic spline analyses. CONCLUSION: A higher protein intake was significantly associated with a more rapid kidney function decline in post-MI patients.

Low Birth Weight and Kidney Function in Middle-Aged Men and Women: The Netherlands Epidemiology of Obesity Study.

RATIONALE & OBJECTIVE: Chronic kidney disease (CKD), defined as estimated glomerular filtration rate (eGFR)<60mL/min/1.73m2, is a risk factor for cardiovascular morbidity and mortality. Little is known about low birth weight and risk for CKD in middle-aged adults in the general population. We estimated the causal association between birth weight and eGFR in a Dutch cohort of middle-aged men and women. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 6,671 participants in the Netherlands Epidemiology of Obesity (NEO) Study. Replication study using data for 133,814 participants studied by the CKDGen consortium. EXPOSURE: Birth weight was self-reported and also based on an instrumental variable, 59 birth weight-associated genetic variants, derived from an independent data source. OUTCOME: eGFR at the age of 45 to 65 years. ANALYTICAL APPROACH: We assessed the association between self-reported birth weight and eGFR in the NEO Study using multivariable linear regression, adjusted for age, sex, education, smoking, and alcohol use. The effect of the instrument on eGFR was estimated using separate 2-sample Mendelian randomization analyses: one using individual data from the NEO cohort and one using summary data from the CKDGen consortium. RESULTS: At baseline, mean eGFR was 86±12.4 (SD) mL/min/1.73m2. After multivariable adjustment, self-reported birth weight was not associated with kidney function in middle age. Two-sample Mendelian randomization analysis showed that in the NEO cohort, for each 500-g lower birth weight defined using genetic variants, there was a 3.7 (95% CI, 0.5-6.9)-mL/min/1.73m2 lower eGFR at the age of 45 to 65 years. However, using CKDGen summary-level data, there was a smaller nonsignificant relationship between birth weight and eGFR. LIMITATIONS: Birth weight was self-reported. CONCLUSIONS: Lower birth weight defined using genetic variants was associated with lower eGFRs in Dutch middle-aged adults. However, this finding was not replicated within the CKDGen consortium.

The predictive value of TIMP-2 and IGFBP7 for kidney failure and 30-day mortality after elective cardiac surgery.

Acute kidney injury (AKI) is an important risk factor for chronic kidney disease, renal replacement therapy (RRT), and mortality. However, predicting AKI with currently available markers remains problematic. We assessed the predictive value of urinary tissue inhibitor of metalloprotease-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) regarding the need for RRT, and 30-day mortality, in elective cardiac surgery patients. In 344 elective cardiac surgery patients, we measured urinary TIMP-2 and IGFBP7 and serum creatinine at baseline and directly after surgery. Discrimination of both urinary biomarkers was assessed by the C-statistic. Model improvement for each biomarker when added to a basic model containing serum creatinine and duration of surgery was tested by the net-reclassification index (cf-NRI) and integrated discrimination index (IDI). At baseline, mean age was 66 years and 67% were men. Of all patients, 22 required RRT following surgery. IGFBP7 pre- and post-surgery and change in TIMP-2 during surgery predicted RRT with a C-statistic of about 0.80. However, a simple model including baseline serum creatinine and duration of surgery had a C-statistic of 0.92, which was improved to 0.93 upon addition of post-surgery TIMP-2 or IGFBP7, with statistically significant cf-NRIs but non-significant IDIs. Post-surgery TIMP-2 and IGFBP predicted 30-day mortality, with C-statistics of 0.74 and 0.80. In conclusion, in elective cardiac surgery patients, pre- and peri-operative clinical variables were highly discriminating about which patients required RRT after surgery. Nonetheless, in elective cardiac surgery patients, urinary TIMP-2 and IGFBP7 improved prediction of RRT and 30-day mortality post-surgery.

Superior Long-term Survival for Simultaneous Pancreas-Kidney Transplantation as Renal Replacement Therapy: 30-Year Follow-up of a Nationwide Cohort.

OBJECTIVE: In patients with type 1 diabetes and end-stage renal disease, it is controversial whether a simultaneous pancreas-kidney (SPK) transplantation improves survival compared with kidney transplantation alone. We compared long-term survival in SPK and living- or deceased-donor kidney transplant recipients. RESEARCH DESIGN AND METHODS: We included all 2,796 patients with type 1 diabetes in the Netherlands who started renal replacement therapy between 1986 and 2016. We used multivariable Cox regression analyses adjusted for recipient age and sex, dialysis modality and vintage, transplantation era, and donor age to compare all-cause mortality between deceased- or living-donor kidney and SPK transplant recipients. Separately, we analyzed mortality between regions where SPK transplant was the preferred intervention (80% SPK) versus regions where a kidney transplant alone was favored (30% SPK). RESULTS: Of 996 transplanted patients, 42%, 16%, and 42% received a deceased- or living-donor kidney or SPK transplant, respectively. Mean (SD) age at transplantation was 50 (11), 48 (11), and 42 (8) years, respectively. Median (95% CI) survival time was 7.3 (6.2; 8.3), 10.5 (7.2; 13.7), and 16.5 (15.1; 17.9) years, respectively. SPK recipients with a functioning pancreas graft at 1 year (91%) had the highest survival (median 17.4 years). Compared with deceased-donor kidney transplant recipients, adjusted hazard ratios (95% CI) for 10- and 20-year all-cause mortality were 0.79 (0.49; 1.29) and 0.98 (0.69; 1.39) for living-donor kidney and 0.67 (0.46; 0.98) and 0.79 (0.60; 1.05) for SPK recipients, respectively. A treatment strategy favoring SPK over kidney transplantation alone showed 10- and 20-year mortality hazard ratios of 0.56 (0.40; 0.78) and 0.69 (0.52; 0.90), respectively. CONCLUSIONS: Compared with living- or deceased-donor kidney transplantation, SPK transplant was associated with improved patient survival, especially in recipients with a long-term functioning pancreatic graft, and resulted in an almost twofold lower 10-year mortality rate.

Cardiovascular Risk Factors Accelerate Kidney Function Decline in Post-Myocardial Infarction Patients: The Alpha Omega Cohort Study.

INTRODUCTION: Impaired kidney function is a robust risk factor for cardiovascular mortality. Age-related annual kidney function decline of 1.0 ml/min per 1.73 m2 after age 40 years is doubled in post-myocardial infarction (MI) patients. METHODS: We investigated the impact of the number of cardiovascular risk factors (including unhealthy lifestyle) on annual kidney function decline, in 2426 post-MI patients (60-80 years) of the prospective Alpha Omega Cohort study. Glomerular filtration rate was estimated by serum cystatin C (eGFRcysC) and combined creatinine-cystatin C (eGFRcr-cysC), using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations from 2012. Data were analyzed by multivariable linear and logistic regression. RESULTS: At baseline, mean (SD) eGFRcysC and eGFRcr-cysC were 81.5 (19.6) and 78.5 (18.7) ml/min per 1.73 m2, respectively. Of all patients, 79% were men, 19% had diabetes, 56% had high blood pressure (≥140/90 mm Hg), 16% were current smokers, 56% had high serum low-density lipoprotein (LDL of ≥2.5 mmol/l), and 23% were obese (body mass index of ≥30.0 kg/m2). After multivariable adjustment, the additional annual eGFRcysC decline (95% confidence interval) was as follows: in patients with versus without diabetes, -0.90 (-1.23 to -0.57) ml/min per 1.73 m2; in patients with high versus normal blood pressure, -0.50 (-0.76 to -0.24) ml/min per 1.73 m2; in obese versus nonobese patients, -0.31 (-0.61 to 0.01) ml/min per 1.73 m2; and in current smokers versus nonsmokers, -0.19 (-0.54 to 0.16) ml/min per 1.73 m2. High LDL was not associated with accelerated eGFRcysC decline. Similar results were obtained with eGFRcr-cysC. CONCLUSION: In older, stable post-MI patients without cardiovascular risk factors, the annual kidney function decline was -0.90 (-1.16 to -0.65) ml/min per 1.73 m2. In contrast, in post-MI patients with ≥3 cardiovascular risk factors, the annual kidney function decline was 2.5-fold faster, at -2.37 (-2.85 to -1.89) ml/min per 1.73 m2.

Body-fat indicators and kidney function decline in older post-myocardial infarction patients: The Alpha Omega Cohort Study.

Background Obesity increases risk of hypertension and diabetes, the leading causes of end-stage renal disease. The effect of obesity on kidney function decline in stable post-myocardial infarction patients is poorly documented. This relation was investigated in a large cohort of older post-myocardial infarction patients. Design Data were analysed from 2410 post-myocardial infarction patients in the Alpha Omega Trial, aged 60-80 years receiving optimal pharmacotherapy treatment (79% men, 18% diabetes). Methods Cystatin C based estimated glomerular filtration rate (eGFRcysC) was calculated at baseline and after 41 months, using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Obesity was defined as body mass index ≥ 30 kg/m2 and high waist circumference as ≥102 and ≥88 cm for men and women. The relation between body mass index, waist circumference and annual eGFRcysC decline was evaluated by linear regression. Results At baseline, mean (standard deviation) eGFRcysC was 81.5 (19.6) ml/min/1.73 m2, 23% of all patients were obese. After multivariable adjustment, the annual mean (95% confidence interval) eGFRcysC decline in men and women was -1.45 (-1.59 to -1.31) and -0.92 (-1.20 to -0.63) ml/min/1.73 m2, respectively ( p = 0.001). Obese versus non-obese patients and patients with high versus normal waist circumference experienced greater annual eGFRcysC decline. Men and women showed an additional annual eGFRcysC decline of -0.35 (-0.56 to -0.14) and -0.21 (-0.55 to 0.14) ml/min/1.73 m2 per 5 kg/m2 body mass index increment ( p for interaction 0.3). Conclusions High compared to normal body mass index or waist circumference were associated with more rapid kidney function decline in older stable post-myocardial infarction patients receiving optimal drug therapy.