Incidence of non-severe hypoglycaemia and intensity of treatment among veterans with type 2 diabetes in the U.S.A.: a prospective observational study.

AIM: To quantify the incidence of non-severe hypoglycaemic events among veterans with Type 2 diabetes and its association with primary care provider prescribing behaviour. METHODS: This was a prospective observational study involving 30 primary care providers and patients enrolled with these primary care providers, identified from computerized pharmacy records. Two sampling frames were created consisting of (1) patients not treated with insulin and receiving sulfonylurea treatment (with or without other oral hypoglycaemic agents) and (2) patients treated with insulin (with or without sulfonylureas or other oral hypoglycaemic agents). Patients recorded the frequency, proximal cause of, and response to each hypoglycaemic event over a 12-week period and made three visits to a research coordinator over 24 weeks. Data were provided to the primary care provider before their next visit and charts were reviewed for medication changes. RESULTS: A total of 265 patients were enrolled in study. During the 12 weeks of structured self-monitoring of blood glucose, patients recorded a mean (sd) of 6.9 (10.3) hypoglycaemic events. Duration of diabetes increased monotonically with increasing category of hypoglycaemic event (P < 0.001). Among insulin users, an increased frequency of hypoglycaemic events was associated with a decreased likelihood of dose intensification by primary care providers (relative risk 0.86 per event; P = 0.02) but no significant increase in tendency for dose reduction (relative risk 1.04 per event; P = 0.06). Increased frequency of hypoglycaemic events was associated with an increased likelihood of dose reduction (relative risk 1.12 per event; P = 0.03) in the sulfonylurea treatment group. CONCLUSIONS: Non-severe hypoglycaemia is common among veterans with Type 2 diabetes receiving insulin or sulfonylureas and influences the prescribing behaviour of primary care providers.

Inadequacy of dialysis, chronic inflammation and malnutrition in Nigerian patients on chronic hemodialysis.

PURPOSE: To identify the extent of underdialysis, chronic inflammation and malnutrition and their interrelationships in Nigerian hemodialysis patients. METHODS: In a prospective study including 10 adult patients, (6 men, 4 women) on hemodialysis in North Central Nigeria, malnutrition was assessed by body mass index (BMI), serum albumin and prealbumin, and bioimpedance (BIA) pre-and post dialysis, inflammation was evaluated by C-reactive protein (CRP) and adequacy of dialysis was judged by frequency of the hemodialysis sessions and Kt/V urea. RESULTS: Post-dialysis BMI was 21.3 (19.9, 24.3) kg/m2 (< 20 kg/m2 in 4 patients), serum albumin 31.5 (24.0, 32.0) g/L (< 30.0 g/L in 5), serum pre-albumin 25.2 (15.3, 31.1) mg/dL (< 18.0 mg/dL in 4), serum CRP 4.8 (1.2, 11.5) mg/dL (> 1.0 mg/dL in 8), phase angle 4.2 (3.7, 5.1) degrees (< 3 degrees in 3) and body fat deficit was diagnosed by BIA in 4 patients. Weekly frequency of dialysis was 3 times in 2 patients, twice in 1 and 1.2 in one patient receiving dialysis only twice weekly). By combined frequency of dialysis and Kt/V urea values, no patient received an adequate dose of dialysis and, indeed, all patients had overt symptoms of uremia. Low body weight, low serological and BIA nutrition indices, and high CRP levels occurred in the same patients. Patients on dialysis for > 1 year had worse nutrition indices than those on dialysis for < 1 year. CONCLUSIONS: Underdialysis was universal, while poor nutrition and chronic malnutrition were found in the majority of the small number of patients studied. These three adverse conditions, which were interlinked, may be common in Nigerian hemodialysis patients, because their underlying socioeconomic causes are widespread.

Factors affecting diabetes knowledge in Type 2 diabetic veterans.

AIMS/HYPOTHESIS: To describe the clinical, psychological and social factors affecting diabetes knowledge of veterans with established Type 2 diabetes. METHODS: We conducted an observational study of 284 insulin-treated veterans with stable Type 2 diabetes. All subjects completed the University of Michigan Diabetes Research and Training Centre Knowledge Test, the Diabetes Care Profile, the Mini-Mental State Examination, the Geriatric Depression Scale, and the Diabetes Family Behaviour Checklist. Stepwise multiple linear regression was used to develop a model for the diabetes knowledge score based upon clinical and psychosocial variables. RESULTS: One hundred eighty subjects were evaluated in a derivation set. The mean age +/- SD was 65.4+/-9.6 years, 94% were men, and 36% were members of a minority group. Performance on the diabetes knowledge test was poor (64.9+/-15.3% correct). Self-perceived understanding of all management objectives explained only 6% of the variance in the knowledge scores. Multivariate analysis showed that age, years of schooling, duration of treatment, cognitive function, sex, and level of depression were independent determinants of the knowledge score. When the model was applied to 104 subjects in a validation set, there was a strong correlation between observed and predicted scores (r=0.537; p<0.001). CONCLUSIONS/INTERPRETATION: Stable, insulin-treated veterans have major deficiencies in diabetes knowledge that could impair their ability to provide self-care. A multivariate model comprised of demographic variables and psychosocial profiling can identify patients who have limited diabetes knowledge and be used to assess individual barriers to ongoing diabetes education.

Water and small solute excretion in continuous peritoneal dialysis patients with lean body mass exceeding 90% of body weight as estimated from creatinine kinetics.

Lean body mass computed from creatinine kinetics (LBM) is an index of somatic nutrition and correlates with other nutrition indices in CAPD. However, LBM exceeding 90% of body weight (LBM/W > or = 0.9) may be an index of non-compliance, rather than nutrition. To test this hypothesis, we analyzed fluid and solute excretion in 40 CAPD patients with LBM/W > or = 0.9 (group A). The comparison group (group B) consisted of 885 CAPD patients with LBM/W < 0.9. Group A was younger (38.3+/-14.8 vs 54.7+/-14.7 yr) and had a lower percent of women (23.5% vs 41.1%) and diabetic subjects (17.5% vs 42.6%) than group B (at P < or = 0.019). Group A also had lower body mass index (22.7+/-2.7 vs 25.8+/-5.1 kg/m2, P <0.001) and serum albumin (33.0+/-6.7 vs 35.2+/-5.5 g/L, P = 0.014). Despite similar prescribed daily fill volumes (group A 8.3+/-2.4, group B 8.5+/-2.2 L/24 h) and similar D/P urea and creatinine values, group A had higher daily drain volume (11.0+/-3.6 vs 9.6+/-2.1 L/24 h, P < 0.001). Renal clearances were similar, while peritoneal and total clearances were apparently higher in group A. Creatinine excretion was higher in group A (27.4+/-5.1 vs 13.6+/-4.1 mg/kg x 24 h, P < 0.001), with a large part of the excess creatinine excretion in group A being accounted for by peritoneal excretion. The combination of an apparently high daily ultrafiltration volume (2.7 L/24 h on the average), unrealistically high creatinine excretion rate, and relatively poor nutrition (low body mass index and serum albumin) in group A is consistent with non-compliance. We suggest that the finding of LBM/W > or = 0.9 during a clearance study in CAPD should trigger an investigation for non-compliance.

Step-down management of gastroesophageal reflux disease.

BACKGROUND & AIMS: As the economic burden of gastroesophageal reflux disease (GERD) is largely weighted to maintenance as opposed to initial therapy, switching from more potent to less expensive medication once symptoms are alleviated (step-down therapy) may prove to be most cost-effective. This study aimed to prospectively evaluate the feasibility of step-down therapy in a cohort of patients with symptoms of uncomplicated GERD. METHODS: Patients whose GERD symptoms were alleviated by proton pump inhibitors (PPIs) were recruited from outpatient general medicine clinics. After baseline demographic and quality of life information were obtained, PPIs were withdrawn from subjects in a stepwise fashion. Primary outcome was recurrence of symptoms during follow-up that required reinstitution of PPIs. Secondary outcomes included changes in quality of life and overall cost of management. Predictors of nonresponse to step-down were assessed. RESULTS: Seventy-one of 73 enrolled subjects completed the study. Forty-one of 71 (58%) were asymptomatic off PPI therapy after 1 year of follow-up. Twenty-four of 71 (34%) required histamine 2-receptor antagonists, 5/71 (7%) prokinetic agents, 1/71 (1%) both, and 11/71 (15%) remained asymptomatic without medication. Quality of life did not significantly change, whereas management costs decreased by 37%. Multivariable analysis revealed younger age and a dominant symptom of heartburn to predict PPI requirement. CONCLUSIONS: Step-down therapy is successful in the majority of patients and can decrease costs without adversely affecting quality of life.

The relation between nutrition indices and age in patients on continuous ambulatory peritoneal dialysis receiving similar small solute clearances.

OBJECTIVE: To analyze the effect of age on nutrition indices in subjects on the same continuous ambulatory peritoneal dialysis (CAPD) schedule. METHODS: We analyzed 613 sets of clearance values and nutrition indices in 302 CAPD patients. Small solute clearances included urea clearance (Kt/Vurea) and creatinine clearance (Ccr). Nutrition indices included body mass index (BMI), serum albumin, urea and creatinine, 24-h urea nitrogen and creatinine excretion in urine plus dialysate, protein nitrogen appearance (PNA), PNA normalized by standard weight (nPNA), lean body mass (LBM) computed by creatinine kinetics, and LBM/Weight. CAPD subjects were classified in 4 age quartiles (Q): Group Q1, age 33.7 +/- 7.6 years, N = 149; group Q2, age 49.5 +/- 3.8 years, N = 158; group Q3, age 61.5 +/- 2.6 years, N = 154; and group Q4, age 72.1 +/- 5.4 years, N = 152. Group comparison was done by one-way ANOVA or chi-square. Predictors of low nutritional parameters were identified by logistic regression. Selected variables were compared by linear regression. RESULTS: Mean Kt/Vurea and Ccr were above the current adequacy standards and did not differ between the age quartiles. In contrast, older quartiles had, in general, lower nutrition indices than younger quartiles. However, the youngest quartile had the lowest BMI. By logistic regression, young age was a predictor of low BMI, while advanced age was a predictor of low creatinine and urea nitrogen excretion, low nPNA, and low LBM/Weight. The regressions of nPNA on Kt/Vurea differed between the age quartiles. By these regressions, the youngest quartile had higher nPNA values for the same Kt/Vurea than the oldest quartile in the clinically relevant range of Kt/Vurea and nPNA values. CONCLUSIONS: Nutrition indices are worse in older than in younger CAPD patients with the same small solute clearances. Nutrition of CAPD patients is adversely affected by age and requires special attention in the older age group.

Creatinine excretion in continuous peritoneal dialysis: a systematic error of the Cockroft-Gault formula.

We investigated the hypothesis that the rate of loss of creatinine excretion with age in peritoneal dialysis (PD) patients differs from the rate predicted from the Cockroft-Gault formula (Cr(Pred)) by analyzing creatinine excretion data obtained from clearance studies of 925 patients on continuous ambulatory PD therapy with an age range of 12 to 91 years. Measured creatinine generation (Cr(Meas)) is the sum of creatinine excretion in urine plus dialysate (Cr(Excr)) plus an estimated metabolic degradation of creatinine. The effect of age on Cr(Excr) and the differences Cr(Excr) - Cr(Pred) and Cr(Meas) - Cr(Pred) were analyzed by linear regression. In 373 women, Cr(Excr) = W(16.9360 - 0.084A), r = -0.342, P < 0.001 (where W is weight in kilograms and A is age in years). The regression slope was one half of the slope in the Cockroft-Gault formula. Cr(Excr) - Cr(Pred) = -413.91 + 4.78A, r = 0.300, P < 0.001. Cr(Meas) - Cr(Pred) = -176.36 + 4.37A, r = 0.278, P < 0.001. In 552 men, Cr(Excr) = W(21.079 - 0.108A), r = -0.338, P < 0.001. The regression slope was approximately one half of the slope in the Cockroft-Gault formula. Cr(Excr) - Cr(Pred) = -493.25 + 6.28A, r = 0.267, P < 0.001. Cr(Meas) - Cr(Pred) = -66.41 + 3.63A, r = 0.143, P = 0.001. The rate of loss of creatinine excretion with age is one half of the rate predicted by the Cockroft-Gault formula in both women and men on PD therapy. Therefore, the difference between excretion (or measured generation) of creatinine and creatinine generation predicted by the Cockroft-Gault formula is not constant, but increases with age. The Cockroft-Gault formula systematically overestimates the effect of age on creatinine excretion in PD patients and is not suitable for predicting creatinine excretion in these subjects.

Disagreement between height/weight classifications of underweight, normal weight, and obesity in peritoneal dialysis patients.

Peritoneal dialysis (PD) patients are classified as underweight, normal weight, or obese by height/weight indices including body mass index (BMI) and the body weight/desired weight (W/DW) ratio. We compared these classifications of degree of obesity in 378 women and 555 men on PD. We used these cut-off values: for underweight, BMI < or = 18.5 and W/DW < or = 0.9; for obesity, BMI > or = 30.0 and W/DW > or = 1.2. The W/DW values were calculated assuming first a small frame, then a medium frame, and finally a large frame for all subjects. Regardless of sex or skeletal frame, BMI correlated highly with W/DW (r value between 0.98 and 0.99); however, the range of BMI values corresponding by linear regression to the normal range of W/DW (0.9-1.2) was narrower than the range of "normal" BMI (18.5-30.0). Consequently, regardless of sex or skeletal frame, smaller fractions of the patient population were classified as underweight or obese by BMI standards than by W/DW standards. The degree of agreement of the classifications of subjects as underweight, normal weight, or obese by BMI and W/DW was evaluated by Cohen's kappa ratio. The kappa ratio varied between 0.47 and 0.58, indicating a reasonable--but not high--degree of agreement beyond chance. The highest kappa ratios were obtained assuming a medium skeletal frame for both women and men. Substantial discrepancies are observed in the classification of PD patients as underweight, normal weight, or obese by BMI and W/DW. Further research is needed to identify the height/weight index that has the strongest association both with clinical outcomes and with other, more precise measurements of body fat content.

Renal clearances in continuous ambulatory peritoneal dialysis: differences between diabetic and non-diabetic subjects.

We analyzed the effect of diabetes on the decline of residual renal function during the course of CAPD in a cross-sectional study including 105 diabetic subjects (41 women) who had 207 clearance studies and 125 non-diabetic subjects (50 women, 265 clearance studies). CAPD duration was 11.5+/-10.5 months in the diabetic group (DG) and 16.8+/-18.6 months in the non-diabetic group (NDG, P < 0.001). The DG had lower urine volume than the NDG (0.52+/-0.46 vs 0.61+/-0.50 L/24-h, P < 0.05), while urine-to-plasma concentration ratio was higher in the DG for creatinine (13.5+/-9.4 vs 11.5+/-11.0, P <0.05) and did not differ for urea. Weekly renal Kt/V urea (DG 0.51+/-0.57, NDG 0.53+/-0.49) and Ccr (DG 31.0+/-28.7 NDG 29.3+/-26.5 L/1.73 m2) did not differ. The slopes of the regressions of CAPD duration on renal clearances did not differ. These regressions allowed estimates of the time, from the onset of CAPD, at which renal clearances become negligible. These estimates differed for both urea clearance (DG 35.3, NDG 50.5 months) and creatinine clearance (DG 43.2, NDG 57.6 months). The slope of the regression of renal urea clearance on renal creatinine clearance was steeper in the DG, suggesting a higher renal creatinine clearance in the DG than in the NDG when renal urea clearance is the same in the two groups. Subtle differences in the rate of decline of renal function can be detected between diabetic and non-diabetic subjects on CAPD by detailed statistical analysis. These findings are supportive of the studies which have identified diabetes mellitus as a predictor of loss of residual renal function during the course of CAPD. In addition, the relationship between the renal urea and creatinine clearances differs between diabetic and nondiabetic subjects on CAPD. Therefore, the dose of CAPD required for adequate total clearances may differ between diabetic and non-diabetic subjects.

Body mass index in patients with amputations on peritoneal dialysis: error of uncorrected estimates and proposed correction.

UNLABELLED: "Weight-height" indices including percent of ideal weight (%IW) and body mass index (BMI) are used to estimate degree of obesity in populations and are predictors of survival in dialysis patients. Amputation affects the relationship between weight and height independently of the degree of obesity. Corrections of both %IW and BMI for amputation have been published, but a National (U.S.) computer nutrition program used in the authors' institution uses only the correction for %IW. This study had two parts: (1) To test whether the weight-height cut-off values for weight deficit (%IW 90%, BMI 20 kg/m2) and obesity (%IW 120%, BMI 30 kg/m2) are compatible, we performed linear regression of BMI on %IW in peritoneal dialysis (PD) patients without amputations. In 349 men, BMI = 0.834 + 0.226 (%IW), r = 0.979. From this regression, the 95% confidence interval (CI) of BMI is 19.2-23.1 kg/m2 if %IW is 90%, and 26.1-29.9 kg/m2 if %IW is 120%. In 260 women, BMI = 2.194 + 0.184 (%IW), r = 0.974. From this regression, the 95% CI of BMI is 15.7-21.8 kg/m2 if %IW is 90%, and 21.3-27.3 kg/m2 if %IW is 120%. (2) To identify the direction and magnitude of the error of uncorrected BMI (BMIu) in dialysis patients with amputations, we analyzed weight-height indices in two groups of men by the computer nutrition program, which corrects %IW, but not BMI for amputation, and by the corrected BMI (BMIc) formula. In group A (amputation without height loss, n = 11), %IW = 110.2% +/- 16.9%, BMIu = 23.6 +/- 2.7 kg/m2, BMIc = 26.4 +/- 3.8 kg/m2 (p < 0.001, BMIc vs BMIu), and 5 of the 11 BMIu values fell below the 95% confidence band of the regression of BMI on %IW in patients without amputations. In group B (amputation with loss of height, n = 6), %IW = 92.7% +/- 19.9%, BMIu = 33.9 +/- 10.7 kg/m2, BMIc = 22.1 +/- 4.4 kg/m2 (p < 0.005, BMIc vs BMIu), and 5 of the 6 BMIu values fell above the 95% confidence band of the regression of BMI on %IW in patients without amputations. CONCLUSIONS: (1) The weight deficit cut-offs for %IW and BMI are compatible in non amputated men and women. (2) The obesity cut-offs for %IW and BMI are compatible in non amputated men, but not in non amputated women. (3) Amputation without height loss decreases BMIu, while amputation with height loss increases, in general, BMIu. (4) BMI should be corrected in PD patients with amputations.

Normalization of clearances in peritoneal dialysis using a formula for body water derived from an end-stage renal disease population.

OBJECTIVE: To compare body water (V) estimates from the Chertow formula (Vc), which was derived in an end-stage renal disease population, to V estimates from the Watson formulas (Vw) in continuous ambulatory peritoneal dialysis (CAPD) patients. To identify CAPD patients in whom Vc is preferred to Vw for clearance studies. DESIGN: Retrospective analysis of clearance studies. SETTING: Dialysis units of four academic medical centers. PARTICIPANTS: 302 subjects on CAPD. INTERVENTION: 613 clearance studies by standard methods. MAIN OUTCOME MEASURES: Comparisons between Vc and Vw, and between urea clearance normalized by Vc [(KtVc)ur] and Vw [(Kt/Vw)ur]. RESULTS: Vc exceeded Vw by 3.5 +/- 1.6 L (p < 0.001), or 9.6% on average. This degree of overestimation of Vw is in the range of body water estimates found in CAPD subjects with severe volume overload (> 5% of body weight) in previous studies. Total (Kt/Nw)ur exceeded total (Kt/Vc)ur by 8.6%. By linear regression, Vc = -0.589 + (1.112 x Vw), r = 0.983. Vw exceeded Vc in only 12 studies. Young age, short height, low body weight, and low prevalence of diabetes characterized the studies with Vw > Vc. Total (Kt/Vw)ur was adequate (> or = 2.0 weekly) in 276 studies. Among these, 74 studies had inadequate total (Kt/Vc)ur (< 2.0 weekly). By logistic regression, the predictors of inadequate (Kt/Vc)ur, when (Kt/Vw)ur was adequate, included the presence of diabetes, great height, and long duration of CAPD. CONCLUSIONS: Vc provides estimates of body water exceeding those provided by Vw in a great majority of CAPD patients. Consequently, approximately 25% of the clearance studies that are adequate when Vw is used as the normalizing parameter may be inadequate when Vc is used. Vc may provide a more appropriate estimate of body water than Vw in CAPD patients with volume overload.

Dependence of peritoneal clearances on body size in continuous ambulatory peritoneal dialysis: effect of the normalizing size indicator.

In peritoneal dialysis (PD), small solute clearances are normalized by body water (V) and body surface area (BSA). The purpose of this study was to identify if V or BSA produced stronger associations between body size and normalized clearances. We studied the relationship between four size indicators (V, BSA, height, and weight) and either peritoneal urea clearance normalized to V (Kt/V(ur)) and BSA (C(ur)) or creatinine clearance normalized to V (Kt/V(cr)) and BSA (C(cr)). A total of 613 clearance studies were performed in subjects on continuous ambulatory peritoneal dialysis (CAPD) with four daily exchanges and a 2 L fill volume. As size increased, the normalized peritoneal clearances decreased in a nonlinear fashion (regression: y = b0 + b1x(-1), where x is a size indicator and y is a normalized clearance). Significant (p < 0.001) negative correlations were found between each normalized clearance and each size indicator. However, in each case, the correlation was higher when V, rather than BSA, was used. For example, BSA correlated more closely with K/V(ur)(-0.660) than C(ur)(-0.556), and also with Kt/V(cr)(-0.579) than C(cr)(-0.446). Normalized clearances are smaller in large subjects on CAPD because one mathematic determinant of the clearance, the drain volume (Dv) normalized by V (Dv/V) or BSA (DV/BSA), decreases as size increases. The relationship between Dv/V or Dv/BSA and the size indicators was studied by the same nonlinear regression model. The correlations of the size indicators with Dv/V were also consistently higher than the corresponding correlations with Dv/BSA. In subjects who were on the same PD schedule, the dependence of clearances on size was consistently higher when V, rather than BSA, was the normalizing parameter. Because prescription of the dose of PD is based on body size, there is a practical advantage by using V as the sole normalizing parameter for both urea and creatinine clearance.

The relation between body size and normalized small solute clearances in continuous ambulatory peritoneal dialysis.

The normalized peritoneal clearances of small solutes depend on the ratio of their concentration in dialysate and plasma (D/P) and the drain volume (Dv) corrected for some measure of body size such as body water (V) or body surface area (BSA). The clearance formulas (D/P) x (Dv/V) and (D/ P) x (Dv/BSA) can be used to examine why large individuals tend to be underdialyzed. Large people have low normalized drain volumes (Dv/V, Dv/BSA). It is not known whether size affects the D/P ratios. The purpose of this study was to examine the relationship between normalized peritoneal clearances (Kt/Vurea, CCr per 1.73 m2 BSA) and four size indicators (weight, height, V, BSA) in 301 patients on continuous ambulatory peritoneal dialysis (four daily exchanges with 2-L exchange volume) who underwent 613 clearance studies. Highly significant (P < 0.001) nonlinear relationships were found between Kt/Vurea and weight (r2 = 0.371), height (r2 = 0.289), BSA (r2 = 0.436), and V (r2 = 0.527); and between CCr and weight (r2 = 0.178), height (r2 = 0.115), BSA (r2 = 0.199), and V (r2 = 0.151). There were also significant negative correlations between the normalized drain volumes (Dv/V and Dv/BSA) and all four indicators of body size. Raw (not normalized) peritoneal clearances and drain volumes correlated positively with size. However, D/P(urea) or D/P(creatinine) did not vary with any size indicator except for a weak association between D/P(creatinine) and V (r = 0.089, P = 0.028). This association was not confirmed when V was used to stratify subjects into quartiles, and group differences for D/P(creatinine were tested by one-way ANOVA. This study shows that the exclusive cause of the low normalized peritoneal clearances in large subjects on continuous ambulatory peritoneal dialysis is a low normalized drain volume. No evidence was found to indicate that body size influences the D/P ratio of small solutes. The portion of the variance in normalized clearance explained by size varies by size indicator and solute (urea versus creatinine).

Gender differences in normalized clearances in CAPD: role of body size and normalizing parameters.

OBJECTIVE: To compare raw (not normalized) and normalized urea and creatinine clearances between women and men on continuous ambulatory peritoneal dialysis (CAPD). To study whether potential gender differences are due to the normalization process. DESIGN: Retrospective analysis of clearance studies. SETTING: Dialysis units of four academic medical centers. PARTICIPANTS: The study included 302 subjects (135 women and 167 men) on CAPD with four daily exchanges and a 2-L exchange volume. INTERVENTION: Measurement of urea and creatinine clearances (261 in women, 352 in men) by standard methods. Body water (the volume of distribution, V, for both urea and creatinine) was estimated by the Watson anthropometric formulas. MAIN OUTCOME MEASURES: Comparison of raw and normalized clearances between women and men. Urea clearance was normalized by V (Kt/Vur), while creatinine clearances was normalized by both V (Kt/Vcr) and body surface area (BSA) (Ccr). RESULTS: Mean values of weekly total (peritoneal plus renal) raw clearances were higher in men (urea clearance: women 67.1 L, men 77.4 L; Ccr: women 61.7 L, men 78.3 L). Raw renal clearances were higher in men, while raw peritoneal clearances were comparable. Mean weekly total Kt/Vur was higher in women (2.19 vs 1.94 in men), mean weekly total Kt/Vcr did not differ between the genders (women 2.01, men 1.95), while mean weekly Ccr was higher in men (73.0 vs 64.7 L/1.73 m2 in women). When clearances differed, the differences were significant at p < 0.001. Men had greater height and weight, while women had greater body mass index. On the average, V in men exceeded V in women by 31%, while BSA in men exceeded BSA in women by only 12%. CONCLUSIONS: Normalization of clearances by V creates relatively higher clearance values in women, while normalization by BSA creates relatively higher clearance values in men. Thus the normalization process may create artificial differences in the normalized clearances between genders.

Small-solute clearances in diabetic subjects on continuous ambulatory peritoneal dialysis: comparison to nondiabetic subjects.

Normalized clearances for urea and creatinine were compared between 121 diabetic subjects (256 clearances) and 181 nondiabetic subjects (357 clearances) on continuous ambulatory peritoneal dialysis (CAPD) with four 2-L exchanges daily. Urea clearance was normalized by VWatson (Kt/Vur), while creatinine clearance was normalized by both VWatson (Kt/Vcr) and body surface area (Ccr). Height, weight, body water (V), and body surface area did not differ between the diabetic and the nondiabetic groups. Also, renal Kt/Vur, renal Kt/Vcr, renal Ccr, and peritoneal Kt/Vur did not differ between the groups. Weekly peritoneal Kt/Vcr (diabetic group 1.36 +/- 0.38, nondiabetic group 1.31 +/- 0.31, p = 0.048) and weekly peritoneal Ccr (diabetic group 47.6 +/- 11.0 L/1.73 m2, nondiabetic group 45.4 +/- 9.2 L/1.73 m2, p = 0.012) were both higher in diabetic subjects. The percentage of high/high-average transporters was higher in the diabetic group (64.9% vs 48.6% in nondiabetic group, p = 0.006). The following total (peritoneal + renal) weekly clearances were obtained: Kt/Vur, diabetic group 2.07 +/- 0.63, nondiabetic group 2.02 +/- 0.56, NS; Kt/Vcr, diabetic group 2.06 +/- 0.78, nondiabetic group 1.92 +/- 0.74, p = 0.026; Ccr, diabetic group 72.7 +/- 28.5 L/1.73 m2, nondiabetic group 67.2 +/- 26.4 L/1.73 m2, p = 0.013. Normalized total creatinine clearances are higher in diabetic subjects than nondiabetic subjects on the same CAPD schedule and with the same renal clearances of urea and creatinine and the same total Kt/Vur, because peritoneal creatinine clearances are higher in the diabetic subjects. This finding is caused by higher peritoneal transport in the diabetic subjects and is not an artifact caused by the normalization process.