Influence of pregnancy on IgA nephropathy

In an attempt to clarify the influence of pregnancy on the natural course of IgA nephropathy, the courses of 79 pregnancies occurring in 47 patients with the disease were studied. These resulted in 3 artificial and 10 spontaneous abortions, and two pre-term and 64 full-term deliveries. Fifty four maternity passbooks were analyzed. In 22 pregnancies (40.7%) proteinuria was increased during the third trimester, and in 13 (76.5%) of 17 pregnancies receiving postpartum urinalysis, urinary protein was decreased to the level of the first trimester within one month after delivery. In two of the remaining four patients with a persistent increase in proteinuria, renal biopsy was carried out two months after delivery, revealing focal glomerular sclerotic lesions, in addition to mild mesangial proliferation compatible with IgA nephropathy. These findings indicated that increased urinary protein observed in the two pregnancies might be attributed to a complication of pre-eclamptic focal glomerular sclerosis rather than exacerbation of underlying IgA nephropathy. The glomerular filtration rate (GFR), examined in 27 patients both before and after pregnancy, was decreased in only two patients (7.4%), but these reductions appeared to go with the individual natural course. In 6 (15.0%) of 40 pregnancies, proteinuria was increased within one month after delivery, and one of them was diagnosed both clinically and pathologically as the acute exacerbation of IgA nephropathy. These data suggest that patients with IgA nephropathy might show transient acute exacerbation just after delivery rather than during pregnancy, and that even if such exacerbations occurred, pregnancy might have little influence on the natural course of the disease.     

An overview of pregnancy in women with underlying renal disease

This is a report of a retrospective study of the effects of preexisting glomerular disease and pregnancy on each other. Two hundred forty pregnancies in 166 Japanese women who delivered between 1970 and 1988 were analyzed. There were 206 (86%) live births, 14 (6%) perinatal deaths, and 20 (8%) spontaneous abortions. Perinatal loss was greatest in women with hypertension and/or glomerular filtration rate (GFR) less than 70 mL/min before conception. Pregnancy did not appear to adversely affect the underlying glomerular disease if GFR was greater than 70 mL/min and blood pressure was below 140/90 mm Hg. However, with moderately impaired renal function (creatinine greater than 124 mumol/L [1.4 mg/dL] or GFR less than 50 mL/min), the long-term prognosis was poorer, despite generally favorable obstetrical outcomes. Gravidas with membranoproliferative glomerulonephritis had the highest rates of hypertension (29%) and decreased renal function (33%) at final follow-up, ie, the type and severity of glomerulonephritis had a major impact on clinical course.     

Glomerular disease and pregnancy. A study of 123 pregnancies in patients with primary and secondary glomerular diseases

The clinical course of 123 pregnancies in 86 patients with biopsy-proven glomerular diseases have been studied. In 35 women the onset of nephropathy occurred during pregnancy. No complications were observed in more than half of the pregnancies. In the others, one third of the complications were obstetrical or fetal accidents, one third were renal manifestations (hypertension or deterioration of renal function) and one third were both causes. The lowest incidence of complications was observed in patients with membranous nephropathy and the highest in membranoproliferative glomerulonephritis patients. There were 6 spontaneous late abortion, 6 stillbirths and 5 neonatal deaths. 17 deliveries were preterm and 7 fetuses were small for gestational age. Hypertension appeared in 24 pregnancies, in 13 of which it was reversible and related to superimposed preeclampsia and in 11 it persisted after delivery (5 of these 11 pregnancies were in patients with IgA nephropathy). Renal function deteriorated in 10 cases during pregnancy. The deterioration was reversible in 6 and progressive in 4 (2 of whom had membranoproliferative glomerulonephritis). It is suggested that in most patients pregnancy does not change the natural history of glomerular disease.     

How pregnancy influences renal function in nephropathic type 1 diabetic women depends on their pre-conceptional creatinine clearance

Pregnancy in type 1 diabetic women with overt nephropathy can lead to a further deterioration in renal function but it is not clear at what level of pre-conceptional GFR the risk for worsening of renal function begins to increase. Therefore we investigated the influence of pregnancy on renal function in 12 women (14 pregnancies) with pre-conceptional macroproteinuria and near-normal creatinine clearance (range 37-93 ml/min/1.73m2). S-creatinine, creatinine clearance (CrCL), HbA1c and blood pressure (BP) were measured before conception, during each trimester (12th and 24th week of gestation and last week before delivery) and three and six months post-partum. In five diabetic women with six pregnancies (group A) there was a physiological increase in CrCl of 36% up until the 24th week of gestation; their pre-conceptional mean CrCl was 80 (range 70-93) ml/min/1.73m2. In seven women with eight pregnancies (group B) CrCl decreased by 16% during the first two trimesters; the mean CrCl before conception was 61 (37-73) ml/min/1.73m2. In the last week before delivery CrCl worsened transiently in three cases in group A and four in group B, due to pre-eclampsia. Three months post-partum the mean CrCl in group A was 78 (70-91) ml/min/1.73m2, approximately the same as before pregnancy. In group B the mean CrCl was 39 (22-68) ml/min/1.73m2 at this same time; this was 36% lower than the pre-conceptional clearance. Mean HbA1c in both groups were approximately the same, but mean BP tended to be higher during pregnancy in group B, especially in the week before delivery (p<0.05). We conclude that in a high percentage of nephropathic diabetic women with significantly low CrCl before conception, renal function worsens during and after pregnancy. Inadequate antihypertensive therapy may contribute to this.     

Repeated pregnancies in patients with primary membranous glomerulonephritis

This retrospective study was carried out in patients with membranous glomerulonephritis (MGN) and repeated pregnancies, the aim being to see how one influences the other. Patients with two or more pregnancies after MGN were included in the study. Nine patients underwent 51 pregnancies (range 2-12, mean 5.6) and 30 were post-MGN (range 2-5, mean 3.2). Their ages were 27-44 (32 +/- 5.7) years. The duration of follow-up was 2-10 (5.6 +/- 2.5) years. The pregnancy outcome, i.e., number of full-term deliveries (FT), spontaneous abortion, preterm deliveries (PT), perinatal mortality (PM), low-birth-weight babies (LBW) and cesarean section (CS), was noted. In the pre-MGN group (n = 21), there were 20 (95.2%) live births and 1 (4.7%) abortion; none had PT, PM, LBW or CS. In the post-MGN group (n = 30), there were 27 (90%) live births, 2 (6.6%) PT, 1 (3.3%) abortion, 1 (3.3%) PM, 3 (10.0%) LBW babies and 3 (10.3%) CS. However, in comparison, there was no statistically significant difference in the pregnancy outcome between the two groups (p > 0.05 in all). Comparing the incidence of hypertension, proteinuria and serum creatinine levels between the first and the last post-MGN pregnancies, there was no statistically significant difference between the two groups. Only 1 patient developed renal insufficiency (serum creatinine 220 micromol/l) after undergoing 5 pregnancies and follow-up of 6 years. In conclusion, the outcome of repeated pregnancies in patients with MGN is good with 90% live births. Repeated pregnancies do not influence the course of MGN.     

Pregnancy in IgA nephropathy.

The impacts of IgA nephropathy and pregnancy on each other were evaluated in 118 women who conceived 168 times between 1970 and 1988. Rates of spontaneous abortion, normal delivery, live birth and perinatal death were 9, 66, 87 and 4%, respectively. Infants born to women with glomerular filtration rates (GFR) lower than 70 ml/min prior to conception had a higher perinatal mortality rate (14% vs. 3%, P less than 0.001). This was also true if pre-pregnancy blood pressures were consistently higher than 140/90 mm Hg (33% vs. 1%, P less than 0.001). These were the figures for the whole 18 year period, but stratification of the data revealed that most adverse results occurred in the 1970's, during which the perinatal death rate was 9%, while it was 0% in the 1980's. Eighty-five women were followed for three years or more. At final follow-up, the rates of decrease in GFR, and increases in blood pressure and proteinuria were 19, 11 and 7%, respectively. In most patients the natural history of IgA nephropathy was similar to that of women who had not experienced pregnancy, but there were five instances where gestation seemed to accelerate functional loss, with rapid development of end-stage or near end-stage renal failure. Most women with IgA nephropathy should anticipate few problems with pregnancy, if they are normotensive and their preconception GFR exceeds 70 ml/min. The gestation in such instances should have little influence on the natural history of their nephropathy.     

Steroid therapy in IgA nephropathy: a retrospective study in heavy proteinuric cases

29 patients with IgA nephropathy whose proteinuria persisted at a level of 2.0 g/day or more and who received prednisolone treatment for 1-3 years were retrospectively evaluated on their clinical courses. 13 of 14 patients with renal dysfunction of less than 70 ml/min in initial creatinine clearance (Ccr) values subsequently entered a progressive course during a follow-up period of 47 months, leading to end-stage renal failure in 8 cases. On the other hand, only 1 of the other 15 patients with preserved renal function of 70 ml/min or more ended up with end-stage renal failure during a follow-up period of 74 months, although 7 underwent a progressive course. Three patients in the latter group experienced a prominent reduction in proteinuria to less than 1.0 g/day and maintained renal function. Meanwhile, the steroid group of moderate proteinuric patients with a creatinine clearance greater than 70 ml/min had a benign course, while the nonsteroid group had an unfavorable one. These results suggest that steroid therapy in IgA nephropathy may be able to stabilize a progressive course, especially in the early stage of the disease, although, because they come from an uncontrolled study, a definite conclusion cannot be drawn.     

Renal survival rate of IgA nephropathy

In an attempt to identify prognostic indicators in IgA nephropathy, we evaluated the relationship between clinical and histological findings and changes in renal function in 81 patients with IgA nephropathy whose creatinine clearance was more than 80 ml/min at the time of renal biopsy. The incidence of patients whose creatinine clearance decreased to less than 60 ml/min during the follow-up period was calculated with the life table method to designate the renal survival rate. This rate was compared according to the clinical and histological findings at the time of renal biopsy. In conclusion, a statistically significant decrease in the renal survival rate was observed in patients with proteinuria of more than 1.0 g/day, hypertension, severe diffuse proliferative glomerulonephritis, diffuse proliferative glomerulonephritis with focal crescents and glomerular deposition of IgM and/or fibrinogen-related antigen.     

What is the best hydration regimen to prevent contrast media-induced nephrotoxicity?

BACKGROUND: Hydration is a commonly used method to prevent the decline in GFR after contrast media (CM) application. So far, there have been no controlled, randomized trials investigating the most effective route of fluid administration. METHODS: Thirty-nine patients with normal renal function (65 +/- 9 years, serum creatinine 0.9 +/- 0.2 mg/dl, GFR = 110 +/- 31 ml/min/1.73 m2) receiving at least 80 ml of low-osmolality CM during an angiographic procedure were randomized to one of the following hydration regimens: Group 1: volume expansion with 300 ml saline during CM administration (n = 20, serum creatinine 0.8 +/- 0.1 mg/dl, GFR 119 +/- 27 ml/min/1.73 m2); Group 2: intravenous administration of at least 2,000 ml saline within 12 h before and after CM application (n = 19, serum creatinine 0.9 +/- 0.2 mg/dl, GFR 101 +/- 32 ml/min/1.73 m2). GFR was measured by CM clearance (Renalyzer) at baseline and 48 hours after CM administration. The primary end point was the mean change in the GFR after 48 hours, the secondary one was the incidence of CM-induced nephropathy (CMIN), defined as a decrease in GFR of more than 50% from the baseline GFR within 48 hours. RESULTS: Patients of group 1 showed a significantly (p < 0.05) higher decline in GFR (delta GFR 34.6 +/- 25.7 ml/min/1.73 m2) compared to patients receiving the intravenous prehydration regimen (delta GFR 18.3 +/- 25.0 ml/min/1.73 m2). The incidence of CMIN was lower in prehydrated patients (5.3%) compared to the other group (15%). CONCLUSION: In patients with normal renal function, intravenous prehydration seems to be a very effective and feasible method to prevent the decline in GFR after contrast media exposure. Volume expansion given only during the CM exposure appears not to be sufficient enough to prevent renal damage.     

Renal Functional Reserve in Pregnancy

Creatinine clearance has been evaluated under baseline conditionsand after acute protein load in five normal and 29 pregnantwomen at different stages of pregnancy without evidence of renaldisease. After a 3-h period in which creatinine clearance wasmeasured hourly (resting GFR), a meal containing 80 g of proteinswas administered and creatinine clearance was measured hourlyfor 4 h (test GFR). Resting GFR in normal sub jects averaged104±22.5 ml/min per 1.73m², the wide variation beingdue to different dietary, protein intake (from 0.3 to 1.2 gof protein per kg body weight). In the pregnant women the resting GFR increased progressivelyfrom the first month (99.8±12.8m1/min per l.73m²) tothe last month of gestation (149.6±12.5 ml/min per 1.73m²) All subjects showed a significant increase of GFR afterprotein load although the greatest difference between the restingand the test GFR was detected in the first trimester. Inulinclearance was also measured in seven subjects after proteinloading to compare creatinine and inulin clearance values. Thetwo clearance values did not differ significantly, showing thatcreatinine can be safely used as a reliable marker for measuringGFR. Test GFR averaged 163.3±4.1 mI/min per 1.73 in normalsubjects and l63.8±6.5 ml/min per l.73m² in pregnantwomen without any relationship with the stage of pregnancy.The identity of test GFR both in normal subjects and in pregnantwomen suggests that this parameter is likely to be related tothe functioning renal mass, and represents the filtration capacityof the kidney. The difference between the test GFR and the resting GFR representsthe renal functional reserve. The progressive increase of theresting GFR during pregnancy suggests a progressive utilisationof the renal functional reserve under the stimuli of gestation.It is evident that only subjects with intact renal functionalreserve may increase their GFR during pregnancy, under specificmetabolic requirements. Acute protein load might be used, therefore,as a simple test to evaluate renal functional reserve and topredict the renal response during future pregnancies. Sincethe test may detect the existence of renal disease even in theearly phases when the reduction of the functioning nephronsis not clinically evident, it might be utilised in some casesto prevent or predict possible pregnancies at risk.     

Serum creatinine is a poor marker of GFR in nephrotic syndrome.

BACKGROUND: In daily clinical practice creatinine clearance is used as marker of glomerular filtration rate (GFR). As a result of the tubular secretion process endogenous creatinine clearance (ECC) overestimates glomerular filtration rate, particularly in patients with impaired renal function. It has been suggested that the tubular handling of creatinine is altered in patients with a nephrotic syndrome. METHODS: Inulin clearance (GFR) and creatinine clearance (ECC) have been simultaneously measured in a cohort of 42 patients with proteinuria and 45 healthy controls. The clearance of creatinine by tubular secretion (TScreat) can be estimated by ECC-GFR. TScreat was calculated in both groups. Regression analysis was performed to identify factors that independently influence tubular creatinine secretion. RESULTS: The mean age (+/-SD) of the patients was 41+/-13 years, serum albumin 26+/-9 g/l, median (IQR) proteinuria 4.5 (3.6-8.2) g/10 mmol creatinine, serum creatinine 103 (84-143) micromol/l, ECC 85 (69-118) ml/min/1.73 m2, and GFR 54 (36-83) ml/min/1.73 m2. Median TScreat amounted to 29 (21-36) ml/min/1.73 m2. In the healthy controls serum creatinine was 75 (70-81) micromol/l, ECC 118 (109-125) ml/min/1.73 m2, GFR 106 (102-115) ml/min/1.73 m2, and TScreat 11 (3.5-19) ml/min/1.73 m2. By regression analysis serum albumin was identified as an independent predictor of tubular creatinine secretion. We divided the patients in two subgroups based on serum albumin levels. TScreat was 24 (14-29) ml/min/1.73 m2 in patients with serum albumin levels >25.8 g/l, and 36 (28-54) ml/min/1.73 m2 in patients with serum albumin levels <25.8 g/l (P<0.01). CONCLUSION: Serum albumin levels influence tubular creatinine secretion. As a result, the endogenous creatinine clearance as well as estimated GFR using a modified MDRD equation more pronouncedly overestimate glomerular filtration rate in nephrotic syndrome.     

Influence of pregnancy on progression of diabetic nephropathy and subsequent requirement of renal replacement therapy in female type I diabetic patients with impaired renal function.

The influence of pregnancy on the progression of diabetic nephropathy in diabetic women with pre-existing moderate renal insufficiency is a subject of considerable controversy in the literature. In four of five female patients with type I diabetes mellitus with pre-existing impaired renal function (creatinine clearance less than 80 ml/min), significant proteinuria (greater than 2 g/24 h urine) and hypertension we have found a further decline in renal function during pregnancy, with an increased deterioration rate of creatinine clearance in comparison to the time before and after pregnancy. The mean decline of the glomerular filtration rate was 1.8 ml/min per month during pregnancy and 1.4 ml/min per month postpartum until the start of dialysis treatment. The difference in the progression of diabetic nephropathy during and after pregnancy can be explained by increased hypertension during pregnancy, especially in the third trimester, despite an intensified antihypertensive therapy. The long-term effect of pregnancy on renal function in our patients was therefore an earlier requirement for renal replacement therapy than would have been expected without pregnancy.     

Deterioration of GFR in IgA nephropathy as measured by 51Cr-EDTA clearance.

In 191 patients with mesangial IgA nephropathy, GFR was determined as clearance of 51Cr-EDTA. 86 (45%) of them had subnormal renal function 7.3 +/- 4.6 years after renal biopsy. The change in GFR was followed in 153 patients with repeated determinations of 51Cr-EDTA clearance. 50.3% of the patients had a loss of more than 1.1 ml/min/year, which we regard as pathological. The markers of progressive disease were: male sex, high output of urinary protein, severe histological lesions and presence of hypertension. Even patients lacking these markers had a significantly increased incidence of progressive disease. Of 93 patients, with initially normal GFR, 32% will have a subnormal GFR within five years and 25% will develop end-stage renal failure within 20 years. In 38 patients with six or more determinations of 51Cr-EDTA clearance, the predictive value of the first four determinations was calculated. Of 26 with a decrease of more than 1.1 ml/min/year, 13 (50%) developed subnormal GFR during follow-up, while 11 of 12 (91.7%) with a decrease of less than 1.1 ml/min/year (P less than 0.05) remained normal. This shows that repeated determinations of GFR with an accurate method will predict the final outcome early in the disease. We also confirmed that single or repeated determinations of clearance of creatinine are of little value in separating a normal GFR from a slightly decreased one, but more reliable in detecting a markedly reduced GFR.     

The effect of pregnancy on kidney function in renal allograft recipients

In women with renal transplants glomerular filtration rate (GFR) increases during pregnancy but how soon the increment occurs, its relation to pre-pregnancy GFR, and the overall pattern of change are unknown. Twenty-four hour creatinine clearance (24-hr CCr) were measured prospectively in ten pregnancies in eight allograft recipients before conception, throughout pregnancy, 8 to 12 weeks postpartum, and 4 to 6 monthly thereafter. Inulin (CIn) in creatinine (CCr) clearances during infusion were also determined and protein excretion was evaluated. The results were compared to those in similar studies in ten healthy women. By the tenth gestational week 24-hr CCr was 124 +/- (SD) 15.9 ml/min in healthy women (an increase of 38%; range, 18 to 69%) and in transplant patients was 105 +/- 28.1 ml/min (an increase of 34%: range, 10 to 60%), with the greatest increments in those whose allografts functioned best before conception, regardless of donor source and sex or the transplant-pregnancy interval. In late pregnancy mean 24-hr CCr decreased by 19% (range, 6 to 28%) in healthy women and by 34% (range, 12 to 57%) in the transplant patients, but in most this did not represent graft deterioration nor lead to permanent impairment. At all time points CIn values were 5 to 10% greater than those for 24-hr CCr but slightly less than infusion CCr values. Protein excretion increased throughout pregnancy and by the third trimester in healthy women averaged 200 mg in 24 hr and regularly exceeded 500 mg in 24 hr in transplant patients, which was three times non-pregnant levels and probably not clinically significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thin basement membrane nephropathy in pregnancy

There are several published series of pregnancy in patients with nonimmunoglobulin A mesangial proliferative glomerulonephritis (most of whom have thin basement membrane nephropathy [TBMN]). The aim of the present study was to review the maternal and fetal outcomes of pregnancy in women with TBMN. The medical and obstetric histories of 86 women with TBMN and their 182 pregnancies (one twin) were reviewed. Data were collected retrospectively in 164 pregnancies (90%) and prospectively in 18 pregnancies (10%). Hypertension (alone or with proteinuria) developed in 15 unmonitored pregnancies (9%), and proteinuria alone developed in the third trimester in 2 pregnancies (1%). Hypertension was more common in the prospectively monitored pregnancies (6 pregnancies, 33%). In all, there were 174 live births (95%), and all fetal deaths occurred in the first and second trimesters in the absence of maternal complications. However, all the mothers of the 4 small for gestational age babies had been hypertensive. In TBMN, maternal hypertension, prematurity, and small for gestational age rates did not exceed those in the normal population. Overall, pregnancy in women with TBMN does not appear to be attended by a significantly increased maternal or fetal risk.     

Performance of the modification of diet in renal disease and Cockcroft-Gault equations in the estimation of GFR in health and in chronic kidney disease

The performance of the Modification of Diet in Renal Disease (MDRD) and the Cockcroft-Gault (CG) equations as compared with measured (125)I-iothalamate GFR (iGFR) was analyzed in patients with chronic kidney disease (CKD) and in potential kidney donors. All outpatients (n = 1285) who underwent an iGFR between 1996 and 2003 were considered for analysis. Of these, 828 patients had CKD and 457 were potential kidney donors. Special emphasis was put on the calibration of the serum creatinine measurements. In CKD patients with GFR <60 ml/min per 1.73 m(2), the MDRD equation performed better than the CG formula with respect to bias (-0.5 versus 3.5 ml/min per 1.73 m(2), respectively) and accuracy within 30% (71 versus 60%, respectively) and 50% (89 versus 77%, respectively). Similar results are reported for 249 CKD patients with diabetes. In the kidney donor group, the MDRD equation significantly underestimated the measured GFR when compared with the CG formula, with a bias of -9.0 versus 1.9 ml/min per 1.73 m(2), respectively (P < 0.01), and both the MDRD and CG equations overestimated the strength of the association of GFR with measured serum creatinine. The present data add further validation of the MDRD equation in outpatients with moderate to advanced kidney disease as well as in those with diabetic nephropathy but suggest that its use is problematic in healthy individuals. This study also emphasizes the complexity of laboratory calibration of serum creatinine measurements, a determining factor when estimating GFR in both healthy individuals and CKD patients with preserved GFR.     

Successful pregnancy in primary glomerular disease

The course of 66 pregnancies was studied in 48 women with primary glomerular diseases. In all cases diagnoses were established by biopsy before pregnancy. They were: membranoproliferative glomerulonephritis in 16 patients, focal glomeruloesclerosis in 13, IgA nephropathy in 10, membranous nephropathy in seven and focal glomerulonephritis in two women. The clinical status of the nephropathy before conception was that 43 had only mild renal dysfunction, five had moderate renal insufficiency, serum creatinine (1.3 to 1.9 mg%), eight women had hypertension (150/100 mm Hg) and eight had nephrotic range proteinuria. Their clinical course was compared with a control group of 36 women with primary glomerular disease who did not become pregnant, and were matched for similar age, histological type, and status of nephropathy (renal function, blood pressure and proteinuria). After one year and at the end of the five year follow-up period, the incidence of hypertension, proteinuria, and renal failure was similar in the two groups. The fetal survival rate was 92%; 51 pregnancies ended in full-term delivery, with a mean birthweight of 3,242 +/- 320 g. There were seven pre-term deliveries (2,170 +/- 135 g), three small for gestational-age (2,340 +/- 135 g), two stillbirths and three spontaneous abortions. These patients had more pre-term deliveries (10.6%) and perinatal mortality (31%) than a normal population (5.5% and 9.6%, respectively). Blood pressure increased during pregnancy in 13 women; in 10 it was reversible, and in four it persisted after delivery. Ten gravidas developed increased proteinuria (reversible in six of them) and two others developed permanent impairment of renal function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Measurement of residual glomerular filtration rate in the patient receiving repetitive hemodialysis.

The objective of the current study was to determine the best index of residual glomerular filtration rate (GFR) by comparing simultaneously measured clearances of inulin, 125I-iothalamate, endogenous creatinine, urea and 169ytterbium diethylenetriaminepentaacetic acid (169YB-DTPA) in patients receiving repetitive hemodialysis. In patients with GFR less than 5 ml/min but greater than 1 ml/min, 125I-iothalamate clearance showed the best correlation with inulin clearance. However, creatinine clearance correlated better with inulin clearance than urea clearance and as well as urea + creatinine/2. In the patients with measured GFR less than 1 ml/min, the correlation of 125I-iothalamate, creatinine, urea and urea + creatinine/two clearances with inulin clearance was satisfactory. Similarly, satisfactory correlations were obtained when the relationships were examined across the entire range of measured clearances less than 5 ml/min. A simple, practical method is descriged for the accurate serial measurement of residual GFR in patients receiving repetitive dialysis.     

Use of the serum creatinine to estimate glomerular filtration rate in health and early diabetic nephropathy. Collaborative Study Group of Angiotensin Converting Enzyme Inhibition in Diabetic Nephropathy

We evaluated 100/serum creatinine, 24-hour creatinine clearance, and simultaneously measured creatinine clearance or creatinine clearance estimated by the formula devised by Cockcroft and Gault in comparison with measurements of glomerular filtration rate (GFR) using iothalamate among 136 patients with diabetic nephropathy. We also evaluated 100/serum creatinine, simultaneously measured creatinine clearance or creatinine clearance estimated by the Cockcroft and Gault formula in comparison with measurements of GFR using inulin among 88 healthy adults, 21 hypercalciuric kidney stone formers and their hypercalciuric relatives, and one man with chronic nephritis. Creatinine clearances measured simultaneously were closely correlated to GFR (r = 0.93) as were creatinine clearances, estimated by the Cockcroft and Gault formula (r = 0.84) when GFR ranged from 16 to 175 mL/min (0.27 to 2.92 mL/s). These observations confirm the clinical use of either creatinine clearances during water diuresis or estimates of creatinine clearance by the Cockcroft and Gault formula in the assessment of kidney function.     

Long-term prognosis of membranous nephropathy

One hundred and four consecutive patients with idiopathic membranous nephropathy have been followed for 24 years. The actuarial survival rates in 5, 10 and 15 years were 94.6, 90.0 and 80.3%, respectively. Within the first 5 years clinical status improved gradually, but thereafter entered into an equilibrated state, when approximately 70% of the patients were in remission of absent (40%) or less than 1.0 g/24 hour urinary protein. As for renal function, within the initial 5 years around 80% of the patients revealed a glomerular filtration rate (GFR) greater than 80 ml/min. This percentage reduced approximately to 70 and 50% over periods of 10 and 15 years, whereas a mean reduction rate of GFR was only 15 ml/min over a period of 8 years. The clinical status at the 5th year correlated well with its outcome (rs = 0.676, p less than 0.001) and GFR estimated around the 5th year with the final estimate (r = 0.796, p less than 0.001). These data suggest that membranous nephropathy follows a fairly good clinical course, and that the 5th year clinical status and renal function are valuable prognostic indices of the disease.