Preeclampsia and the risk of end-stage renal disease

BACKGROUND

It is unknown whether preeclampsia is a risk marker for subsequent end-stage renal disease (ESRD).

METHODS

We linked data from the Medical Birth Registry of Norway, which contains data on all births in Norway since 1967, with data from the Norwegian Renal Registry, which contains data on all patients receiving a diagnosis of end-stage renal disease (ESRD) since 1980, to assess the association between preeclampsia in one or more pregnancies and the subsequent development of ESRD. The study population consisted of women who had had a first singleton birth between 1967 and 1991; we included data from up to three pregnancies.

RESULTS

ESRD developed in 477 of 570,433 women a mean (+/-SD) of 17+/-9 years after the first pregnancy (overall rate, 3.7 per 100,000 women per year). Among women who had been pregnant one or more times, preeclampsia during the first pregnancy was associated with a relative risk of ESRD of 4.7 (95% confidence interval [CI], 3.6 to 6.1). Among women who had been pregnant two or more times, preeclampsia during the first pregnancy was associated with a relative risk of ESRD of 3.2 (95% CI, 2.2 to 4.9), preeclampsia during the second pregnancy with a relative risk of 6.7 (95% CI, 4.3 to 10.6), and preeclampsia during both pregnancies with a relative risk of 6.4 (95% CI, 3.0 to 13.5). Among women who had been pregnant three or more times, preeclampsia during one pregnancy was associated with a relative risk of ESRD of 6.3 (95% CI, 4.1 to 9.9), and preeclampsia during two or three pregnancies was associated with a relative risk of 15.5 (95% CI, 7.8 to 30.8). Having a low-birth-weight or preterm infant increased the relative risk of ESRD. The results were similar after adjustment for possible confounders and after exclusion of women who had kidney disease, rheumatic disease, essential hypertension, or diabetes mellitus before pregnancy.

CONCLUSIONS

Although the absolute risk of ESRD in women who have had preeclampsia is low, preeclampsia is a marker for an increased risk of subsequent ESRD.

Low birth weight increases risk for end-stage renal disease

Case-control studies have shown an association between low birth weight and risk for renal failure. The Medical Birth Registry of Norway, which comprises data on all births in Norway since 1967, and the Norwegian Renal Registry, which comprises data on all patients who have developed ESRD in Norway since 1980, were used to examine whether birth-related variables were associated with risk for ESRD. Of the 2,183,317 children born between 1967 and 2004, 526 were found in the ESRD registry. Compared with birth weight in the 10th to 90th percentiles, births <10th percentile had a relative risk (RR) for ESRD of 1.7 (95% confidence interval 1.4 to 2.2; P < 0.001). Births with a weight for gestational age <10th percentile had an RR of 1.5 (95% confidence interval 1.2 to 1.9; P = 0.002). These associations were virtually identical after adjustment for birth-related confounders such as congenital malformations, multiple delivery, maternal age at birth, and maternal preeclampsia. Low birth weight was more strongly associated with development of ESRD during the first 14 years of life than after age 15. Low birth weight and low birth weight for gestational age were similarly associated with multiple causes of ESRD. In conclusion, in this cohort study with a maximum follow-up of 38 years, low birth weight and intrauterine growth restriction were associated with increased risk for ESRD.

Long-term risk of cancer in membranous nephropathy patients

BACKGROUND

There is a well-known association between membranous nephropathy (MN) and cancer, and patients with MN usually are examined for cancer at the time of diagnosis. The long-term risk of cancer after MN is not well studied.

STUDY DESIGN

Cohort study with record linkage between the Norwegian Kidney Biopsy Registry and Norwegian Cancer Registry.

SETTING & PARTICIPANTS

161 patients with MN from 1988 to 2003.

PREDICTOR

Patients with MN compared with the age- and sex-adjusted general Norwegian population.

OUTCOMES

Cancer diagnosis reported through 2003.

RESULTS

Mean duration of follow-up was 6.2 years (range, 0.1 to 15 years). 33 patients developed cancer; including 24 patients with cancer after the diagnosis of MN. Median time from diagnosis of MN to diagnosis of cancer was 60 months (range, 0 to 157 months). Mean annual incidence ratio of cancer was 2.4/100 person-years (2.1/100 person-years in the 0- to 5-year period and 2.8/100 person-years for the 5 to 15 years after kidney biopsy). During the 0 to 15 years after the diagnosis of MN, the expected number of cancers was 10.7, resulting in a standardized incidence ratio of cancer of 2.25 (95% confidence interval, 1.44 to 3.35). In the 5 to 15 years after diagnosis, standardized incidence ratio was 2.30 (95% confidence interval, 1.19 to 4.02). Patients with MN who developed cancer were older (65 versus 52 years; P < 0.001). Patients with cancer and MN had a greater mortality rate than patients without cancer (67% versus 26%; P < 0.001).

LIMITATIONS

Follow-up treatment after MN with cytotoxic and immunosuppressive medications is not known.

CONCLUSIONS

An increased risk of developing cancer is observed after the diagnosis of MN, which persists for many years.

Adverse perinatal outcome and later kidney biopsy in the mother

Strong associations of adverse perinatal outcomes have been identified with later cardiovascular disease in the mother. Few studies have addressed associations with kidney disease. This study investigated whether perinatal outcomes are associated with later clinical kidney disease as diagnosed by kidney biopsy. The Medical Birth Registry of Norway contains data on all childbirths in Norway since 1967. The Norwegian Kidney Biopsy Registry contains data on all kidney biopsies in Norway since 1988. All women with a first singleton delivery from 1967 to 1998 were included. Pregnancy-related predictors of later kidney biopsy were analyzed by Cox regression analyses. A total of 756,420 women were included, and after a mean period of 15.9+/-9.4 yr, 588 had a kidney biopsy. Compared with women without preeclampsia and with offspring with birth weight of >or=2.5 kg, women with no preeclampsia and with offspring with birth weight of 1.5 to 2.5 kg had a relative risk (RR) for a later kidney biopsy of 1.7, women with no preeclampsia and with offspring with birth weight of <1.5 kg had an RR of 2.9, women with preeclampsia and with offspring with a birth weight of >or=2.5 kg had an RR of 2.5, women with preeclampsia and with offspring with a birth weight of 1.5 to 2.5 kg had an RR of 4.5, and women with preeclampsia and with offspring with a birth weight of <1.5 kg had an RR of 17. Similar results were found in adjusted analyses and after exclusion of women with diabetes, kidney disease, or rheumatic disease before pregnancy. The same risk patterns applied to any of the specific categories of kidney disease as well as specific kidney diseases investigated. Women who have preeclampsia and give birth to offspring with low birth weight and short gestation have a substantially increased risk for having a later kidney biopsy.

Clinical prognostic factors in biopsy-proven benign nephrosclerosis

BACKGROUND

Hypertensive renal damage has become one of the most important causes of end-stage renal failure (ESRF) in Western countries. Affected patients rarely have a kidney biopsy and their diagnoses therefore remain uncertain. The objective of the present study was to examine patients suspected of renal glomerular disease, which at biopsy proved to have isolated benign nephrosclerosis. We wanted to study the effect of different clinical and laboratory variables at the time of biopsy on the short-term and long-term progression to ESRF and death.

METHODS

We retrospectively examined 102 patients who were diagnosed by kidney biopsy in Norway between April 1988 and December 1990. All patients were followed by means of registries for approximately 13 years to describe renal and patient survival.

RESULTS

The age of the patients at the time of biopsy was 55+/-15 years (range 15-88 years). Three years after the time of biopsy, 18% had developed ESRF and 24% had died; the corresponding numbers 13 years after biopsy were 32% and 47%. By Kaplan-Meier analyses, the following variables indicated short-term progression to ESRF: serum creatinine > or = 200 micro mol/l, systolic blood pressure > or = 160 mmHg and proteinuria > or = 1 g/24 h. In addition, patients with increased diastolic blood pressure, increased age and decreased serum albumin tended to develop ESRF more often. Long-term predictors of ESRF in Kaplan-Meier analyses were increased serum creatinine and urinary protein. Independent risk factors for progression to ESRF were increased serum creatinine and increased urinary protein. Independent risk factors for death were increased age and increased serum creatinine.

CONCLUSIONS

Benign nephrosclerosis is a common condition that is associated with a high morbidity and mortality. Short-term predictors of ESRF differ from long-term predictors and this may reflect a pathophysiologically meaningful difference.

Prognostic factors in mesangioproliferative glomerulonephritis

BACKGROUND

The aim of our study was to examine patients with mesangioproliferative glomerulonephritis (MPGN), with or without glomerular IgA deposits, and to analyse the effect of different clinical and histopathological variables at the time of biopsy on progression to end-stage renal failure (ESRF) and death.

METHODS

We retrospectively examined 273 patients who got this diagnosis in Norway from April 1988 to December 1990 after a renal biopsy. All patients were followed for a median duration of 34.8 months (0.8-68 months).

RESULTS

The mean age at the time of biopsy was 40+/-17 years (range 1.1-79 years). Glomerular IgA deposits were present in 45% of the patients; IgA deposits did not affect prognosis. Three years after the time of biopsy, 7% had developed ESRF (chronic dialysis treatment or kidney transplantation) and 8% had died. By Kaplan-Meier analyses, the following clinical variables indicated progression to ESRF: increased serum creatinine, proteinuria > or =1 g/24 h, systolic blood pressure (BP) > or =160 mmHg, diastolic BP > or =90 mmHg, serum albumin <35 g/l, presence of urinary granular casts and age > or =60 years. Morphological variables indicating progression to ESRF were presence of focal mesangial sclerosis, focal glomerular crescents or necroses, benign nephrosclerosis and increased interstitial score. In the multivariable analysis, the following variables indicated progression to ESRF: increased serum creatinine (P<0.001), decreased serum albumin (P<0.05), increased diastolic BP (P<0.05), low age (P<0.05) and increased interstitial score (P<0.001).

CONCLUSIONS

It is possible from clinical and histopathological variables to identify low-risk and high-risk patients at the time of biopsy. There is, however, considerable convergence. A major new observation is the finding of young age, decreased serum albumin and the presence of urinary granular casts as important clinical risk factors. Interstitial damage was the most important histopathological predictor of ESRF.