Impact of pioglitazone on bone mineral density and bone marrow fat content.

Pioglitazone use is associated with an increased risk of fractures. In this randomized, placebo-controlled study, pioglitazone use for 12 months was associated with a significant increase in bone marrow fat content at the femoral neck, accompanied by a significant decrease in total hip bone mineral density. The change in bone marrow fat with pioglitazone use was predominantly observed in female vs. male participants. INTRODUCTION: Use of the insulin sensitizer pioglitazone is associated with greater fracture incidence, although the underlying mechanisms are incompletely understood. This study aimed to assess the effect of pioglitazone treatment on femoral neck bone marrow (BM) fat content and on bone mineral density (BMD), and to establish if any correlation exists between the changes in these parameters. METHODS: In this double-blind placebo-controlled clinical trial, 42 obese volunteers with metabolic syndrome were randomized to pioglitazone (45 mg/day) or matching placebo for 1 year. The following measurements were conducted at baseline and during the treatment: liver, pancreas, and femoral neck BM fat content (by magnetic resonance spectroscopy), BMD by DXA, abdominal subcutaneous and visceral fat, and beta-cell function and insulin sensitivity. RESULTS: Results were available for 37 subjects who completed the baseline and 1-year evaluations. At 12 months, BM fat increased with pioglitazone (absolute change, +4.1%, p = 0.03), whereas BM fat content in the placebo group decreased non-significantly (-3.1%, p = 0.08) (p = 0.007 for the pioglitazone-placebo response difference). Total hip BMD declined in the pioglitazone group (-1.4%) and increased by 0.8% in the placebo group (p = 0.03 between groups). The change in total hip BMD was inversely and significantly correlated with the change in BM fat content (Spearman rho = -0.56, p = 0.01) in the pioglitazone group, but not within the placebo group (rho = -0.29, p = 0.24). Changes in BM fat with pioglitazone were predominantly observed in female vs. male subjects. CONCLUSIONS: Pioglitazone use for 12 months compared with placebo is associated with significant increase in BM fat content at the femoral neck, accompanied by a small but significant decrease in total hip BMD.

Determinants of change in bone mineral density and fracture risk during bisphosphonate holiday.

UNLABELLED: In a retrospective analysis of 208 osteoporotic patients followed during a bisphosphonate holiday, lower body weight and risedronate use were associated with a more rapid decline in bone mineral density during the bisphosphonate holiday, while bone mineral density (BMD) trends were similar in patients who sustained vs. did not sustain a fracture. INTRODUCTION: A drug holiday has been suggested for some bisphosphonate-treated patients with osteoporosis to minimize potential side effects from prolonged use. However, there is limited information on the evolution of BMD during a bisphosphonate holiday. Our study analyzed the longitudinal course of BMD following bisphosphonate discontinuation and assessed its determinants. METHODS: Retrospective single-center cohort study of osteoporosis patients treated with alendronate or risedronate for at least 2 years and then discontinued their bisphosphonate for a drug holiday. Patients were stratified by bisphosphonate type and by fracture occurrence during drug holiday. RESULTS: A total of 208 patients were included in this analysis (87.5 % female). At the time of bisphosphonate cessation, mean ± SD age was 66.9 ± 8.9 years and BMI 24.5 ± 4.4 kg/m(2). Duration of bisphosphonate treatment was 5.2 ± 2.3 years, and follow-up during holiday was 3.3 ± 1.7 years. During the first 2 years of the holiday, BMD remained stable at the lumbar spine and femoral neck, but declined significantly at the total hip. BMD declined significantly at all sites thereafter. Significant predictors of BMD decline during bisphosphonate holiday included lower BMI at the start of the holiday and change in body weight during the holiday. BMD decline was more pronounced in former risedronate compared to former alendronate users. BMD trends were similar in patients who sustained vs. did not sustain a fracture during the holiday. CONCLUSIONS: BMD at the total hip declines significantly within 1 year of bisphosphonate discontinuation, particularly in lean patients. Additional studies are needed to identify predictors of fracture incidence during a bisphosphonate holiday.

Acute and chronic immune biomarker changes during interferon/ribavirin treatment in HIV/HCV co-infected patients.

Chronic viral infections lead to persistent immune activation, which is alleviated by eradicating or suppressing the infection. To understand the effects of interferon treatment on immune system activation by chronic infections, we evaluated kinetic patterns of a broad spectrum of serum biomarkers during HCV treatment in HIV/HCV co-infected patients. HCV viral load and 50 biomarkers were analysed at baseline and 27 time points during pegylated interferon-alpha and ribavirin (IFN/RBV) treatment of 12 HIV/HCV co-infected patients. We evaluated biomarker changes from baseline for each time point and biomarker correlations with clinical parameters, treatment response and liver histopathology. IL-1α, IL-12p40, IL-1RA, IP-10, MIG, MIP-1α/1ß, HGF, sCD40L, TRAIL and leptin increased in the first day. IL-12p70, IL-17A, IL-10, GROα, IL-8, MCP-3, IL-4 and M-CSF peaked later during week 1. IL-1α, HGF, IP-10, MIP-1α, TRAIL, sCD40L, IL-10, IL-12p70, MCP-3, FGFb, ENA-78, TGF-ß, IL-2, IFN-γ, IL-6, IL-15, IL-7 and PDGF-BB decreased below baseline over the course of treatment. Higher BMI, baseline HCV viral load and leptin levels were associated with lack of sustained virologic response. ENA-78 was associated with sustained viral response. Positive correlations were found between liver inflammation and baseline CD4 count, sVCAM and HGF; fibrosis stage and HGF; liver steatosis, BMI and leptin. Our findings suggest IFN/RBV treatment initially increases levels of several biomarkers, but eventually leads to a decline in many immune markers. These findings shed light on the relationship between IFN treatment and immune activation by chronic viral infections, such as HCV.

A multicentre, cross-sectional study on quality of life in patients with cutaneous lupus erythematosus.

BACKGROUND: A study at the University of Pennsylvania (UPenn) Medical Center demonstrated that quality of life in patients with cutaneous lupus erythematosus (CLE) is negatively impacted. Whether patients with CLE in other geographic locations have similar quality of life is unknown. OBJECTIVES: We sought to compare quality of life indicators between patients with CLE at the University of Texas Southwestern (UTSW) Medical Center at Dallas and those at UPenn. METHODS: Patients with CLE (total n=248) at UTSW (n=91) and UPenn (n=157) completed the Skindex-29 +3 and Short Form-36 (SF-36) surveys related to quality of life. Additional information, including demographics, presence of systemic lupus erythematosus (SLE) and disease severity, was collected from UTSW patients with CLE. RESULTS: Most Skindex-29 + 3 and SF-36 subdomain scores between UTSW and UPenn patients with CLE were similar. However, UTSW patients with CLE were significantly more affected in the functioning and lupus-specific Skindex-29 + 3 domains, and physical functioning, role-physical and general health SF-36 subscales than UPenn patients with CLE (P<0·05). Factors related to poor quality of life in UTSW patients with CLE include sex, income, education, presence of SLE, and skin disease activity. CONCLUSIONS: Most quality of life indicators were similar between the two CLE populations. Differences in psychosocial behaviour, and a larger proportion of patients with SLE and females in the UTSW group likely attributed to differences in a minority of Skindex-29+3 and SF-36 subdomains. Capturing data from CLE populations in different locations provides a more thorough picture of the quality of life that patients with CLE experience on a daily basis with special attention to quality of life issues in select patients with CLE.

25-Hydroxyvitamin D levels in African-American and Caucasian/Hispanic subjects with cutaneous lupus erythematosus.

BACKGROUND: Because exposure to ultraviolet radiation accounts for a significant portion of endogenous vitamin D production, subjects with cutaneous lupus (CLE) who practise sun-protective measures are at risk for vitamin D insufficiency. Previous studies have shown light-skinned subjects with CLE to have lower serum 25-hydroxy (25-OH) vitamin D levels than normal controls. OBJECTIVES: To assess the status of vitamin D insufficiency in dark-skinned individuals with CLE. METHODS: We performed a cross-sectional study comparing serum 25-OH vitamin D levels in 25 African-American (AA) subjects with CLE and 26 normal AA subjects matched by age, sex and season in Dallas, Texas. A questionnaire on demographics, medical history and lifestyle habits was administered to determine factors potentially affecting vitamin D levels. Findings were contrasted to a similar comparison in 26 Caucasian and Hispanic (C/H) subjects with CLE and 24 normal C/H subjects matched by age, sex and season. RESULTS: We found similar mean±SD 25-OH vitamin D levels in AA subjects with CLE (52·0±18·5nmolL(-1) ) and normal AA subjects (54·8±21·2 nmolL(-1) ) (P=0·62). Almost half of AA subjects in both groups were vitamin D insufficient. A larger difference in 25-OH vitamin D levels was found between C/H subjects with CLE (59·4±21·0nmolL(-1) ) and normal C/H subjects (70·5±27·4nmolL(-1) ) (P=0·12). Two-way anova demonstrated that skin colour (AA vs. C/H) had a significant effect on 25-OH vitamin D levels (P=0·008), although CLE status (CLE vs. normal) did not (P=0·13). CONCLUSIONS: Providers are encouraged to address vitamin D insufficiency concerns in all dark-skinned individuals. Future studies should stratify subjects by skin colour in determining differences between subjects with CLE and normal controls.

A pilot study to investigate the effect of plate size on meal energy intake in normal weight and overweight/obese women.

BACKGROUND: Smaller plates are often recommended as a strategy for controlling energy intake; however, the effect of plate size on meal energy intake in normal weight compared to overweight or obese individuals is not known. The present study aimed to investigate this further. METHODS: Ten normal weight [mean (SD) body mass index, 21.7 (2.0) kg m(-2) ] and 10 overweight or obese [31.7 (3.6) kg m(-2) ] women attended a metabolic laboratory on two separate days for lunch. In this cross-over study, subjects were randomly assigned to eat lunch using either a small (21.6 cm) or a large (27.4 cm) plate. Each subject self-served spaghetti mixed with tomato sauce from an individual serving bowl onto the assigned plate, and ate until satisfied. The meal was consumed alone at a private table. During the second study day, each subject underwent the same procedure but used the alternate size plate. The amount eaten and energy consumed were calculated and a mixed effects analysis of variance model was used to compare energy intakes. RESULTS: Energy intakes using the small and large plate were 1356 (515) and 1365 (393) kJ, respectively, in normal weight subjects and 1314 (632) and 1226 (431) kJ, respectively, in overweight/obese subjects. Neither plate size, nor plate size by weight status significantly affected meal energy intake. There was no plate size by weight status effect on ratings of palatability, hunger, satiety, fullness or prospective consumption. CONCLUSIONS: Plate size did not affect energy intake from a single meal in either the normal weight or overweight/obese subjects.

Comparison of the absorption of calcium carbonate and calcium citrate after Roux-en-Y gastric bypass.

INTRODUCTION: Roux-en-Y gastric bypass (RYGB) restricts food intake. Consequently, patients consume less calcium. In addition, food no longer passes through the duodenum, the main site of calcium absorption. Therefore, calcium absorption is significantly impaired. The goal of this study is to compare two common calcium supplements in gastric bypass patients. METHOD: Nineteen patients were enrolled in a randomized, double-blinded, crossover study comparing the absorption of calcium from calcium carbonate and calcium citrate salts. Serum and urine calcium levels were assessed for peak values (C (max)) and cumulative calcium increment (area under the curve [AUC]). Serum PTH was assessed for minimum values (PTH(min)) and cumulative PTH decrement (AUC). Statistical analysis was performed using a repeated analysis of variance model. RESULTS: Eighteen subjects completed the study. Calcium citrate resulted in a significantly higher serum C (max) (9.4 + 0.4 mg/dl vs. 9.2 + 0.3 mg/dl, p = 0.02) and serum AUC (55 + 2 mg/dl vs. 54 + 2 mg/dl, p = 0.02). Calcium citrate resulted in a significantly lower PTH(min) (24 + 11 pg/ml vs. 30 + 13 pg/ml, p = 0.01) and a higher AUC (-32 + 51 pg/ml vs. -3 + 56 pg/ml, p = 0.04). There was a non-significant trend for higher urinary AUC in the calcium citrate group (76.13 + 36.39 mg/6 h vs. 66.04 + 40.82, p = 0.17). CONCLUSION: Calcium citrate has superior bioavailability than calcium carbonate in RYGB patients.

Relationship of psoriasis severity to obesity using same-gender siblings as controls for obesity.

BACKGROUND: Psoriasis is a multifactorial disease affected by both genetic and environmental factors. Several comorbid conditions, such as smoking, depression and obesity have been found to be associated with psoriasis. This study addressed the association of psoriasis and obesity using same-gender full siblings as controls, correlating between body mass index (BMI) and severity of psoriasis as determined by body surface area (BSA) and the Physician's Global Assessment (PGA). METHODS: In total, 88 patients undergoing outpatient treatment for psoriasis were surveyed for demographic information, psoriasis history, social history, personal and family medical history, whether they had a same-gender full sibling and if so, the age, weight and height of the sibling. Height, weight, PGA scores and percentage of BSA affected by psoriasis, were recorded for each patient. BMI was calculated for each patient and their same-gender full sibling. RESULTS: A positive association between psoriasis severity and BMI was found. PGA score increased with BMI (Spearman's correlation, r(s) = 0.29, P = 0.007). There was also a positive correlation between BMI and BSA%, r(s) = 0.24, P = 0.02. A significant difference in BMI between patients with psoriasis and the same-gender full sibling control was seen for women (mean +/- SD 30.2 +/- 10.2 vs. 27.6 +/- 7.3 kg/m(2), respectively, P = 0.02), but not for men. CONCLUSION: In this study, psoriasis severity was found to be related to the level of obesity. Using same-gender siblings as genetic controls for predisposition to both obesity and psoriasis, patients with psoriasis were more likely to have a higher BMI, particularly for women. This study reinforces the need to treat the whole patient and to encourage healthy living, such as maintaining an appropriate weight, proper eating habits and exercise. Limitations of this study include the relatively small number of patients enrolled, potential inaccuracies in sibling BMIs calculated from information provided by patients, and a lack of information about dietary habits, exercise and lifestyle.

Increased fibrosis and angiogenesis in subcutaneous gluteal adipose tissue in nascent metabolic syndrome.

AIMS: Metabolic syndrome (MetS) is globally a common disorder that predisposes to both diabetes and cardiovascular disease (CVD). There is a paucity of data on fibrosis and angiogenesis in adipose tissue (AT) in patients with nascent MetS uncomplicated by diabetes or CVD. Hence, we assayed various indices of fibrosis and angiogenesis in subcutaneous AT (SAT). METHODS: In both patients with MetS and matched controls, we determined fibrosis and the densities of CD31, VEGF and Angiopoietin (Angio) 2 and 1 by immunohistochemistry in gluteal SAT. RESULTS: The fibrosis score was significantly increased in SAT of Met S. Also, both CD31 and VEGF densities were significantly increased. Surprisingly, Angio-2 was not increased and the ratio of Angio2:1 was decreased. Both indices of fibrosis and angiogenesis correlated with biomediators of inflammation. CONCLUSIONS: In conclusion, we report increased fibrosis and paradoxical increased angiogenesis in gluteal SAT and speculate that the increased angiogenesis is a protective mechanism in mitigating further adipose tissue dysregulation in this depot.

Comparison of visceral fat mass measurement by dual-X-ray absorptiometry and magnetic resonance imaging in a multiethnic cohort: the Dallas Heart Study.

BACKGROUND/OBJECTIVES: Visceral adipose tissue (VAT) mass, a risk factor for cardiometabolic complications of obesity, is usually measured by magnetic resonance imaging (MRI) but this method is not practical in a clinical setting. In contrast, measurement of VAT by dual-x-ray absorptiometry (DXA) appears to circumvent the limitations of MRI. In this study, we compared measurements of VAT mass by MRI and DXA in the large, multiethnic cohort of the Dallas Heart Study (DHS). SUBJECTS/METHODS: About 2689 DHS participants underwent paired measurement of VAT by MRI and DXA. Sex-stratified analyses were performed to evaluate the correlation and agreement between DXA and MRI. Model validation was performed using bootstrapping and inter-reader variability was assessed. RESULTS: Mean age of the cohort was 44 years, with 55% female, 48% Black and 75% overweight/obese participants. Regression analysis showed a linear relationship between DXA and MRI with R(2)=0.82 (95% confidence interval (CI) 0.81-0.84) for females and R(2)=0.86 (95% CI 0.85-0.88) for males. Mean difference between methods was 0.01 kg for females and 0.09 kg for males. Bland-Altman analysis showed that DXA tended to modestly underestimate VAT compared with MRI at lower VAT levels and overestimate it compared with MRI at higher VAT levels. Results were consistent in analyses stratified by race, body mass index status, waist girth and body fat. Inter-individual reader correlation among 50 randomly selected scans was excellent (inter-class correlation coefficient=0.997). CONCLUSIONS: VAT mass quantification by DXA was both accurate and valid among a large, multiethnic cohort within a wide range of body fatness. Further studies including repeat assessments over time will help determine its long-term applicability.

Effect of hydroxymethyl glutaryl coenzyme a reductase inhibitor therapy on high sensitive C-reactive protein levels.

BACKGROUND: Prospective studies indicate that baseline levels of C-reactive protein (CRP), the prototypic marker of inflammation, are associated with an increased risk for cardiovascular events. Limited studies have examined therapies that influence high-sensitive CRP (hs-CRP) levels, especially in hyperlipidemic patients. Thus, we tested the effects of 3 hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins), simvastatin (20 mg/d), pravastatin (40 mg/d), and atorvastatin (10 mg/d), on levels of hs-CRP in a randomized, double-blind, crossover trial of 22 patients with combined hyperlipidemia (LDL cholesterol >130 mg/dL and triglycerides of 200 to 600 mg/dL). METHODS AND RESULTS: After 6 weeks of an American Heart Association Step 1 diet, fasting blood samples were drawn at baseline and after 6 weeks of therapy with each drug. hs-CRP levels were significantly decreased after treatment with all 3 statins compared with baseline (median values: baseline, 2.6 mg/L; atorvastatin, 1.7 mg/L; simvastatin, 1.7 mg/L; and pravastatin, 1.9 mg/L; P<0.025). The reductions obtained with the 3 statins were similar. In addition, there was no significant effect on either plasma interleukin-6 or interleukin-6 soluble receptor levels. There was no relationship between reductions in hs-CRP and LDL cholesterol. CONCLUSIONS: Pravastatin, simvastatin, and atorvastatin significantly decreased levels of hs-CRP. These data support an anti-inflammatory effect of these drugs.

Obesity-independent hyperinsulinemia in nondiabetic first-degree relatives of individuals with type 2 diabetes.

A close association between obesity and hyperinsulinemia is well recognized, but it is not known whether this relationship is affected by the genetic susceptibility to type 2 diabetes. Insulin response to a 75-g oral glucose load was evaluated in healthy nondiabetic Caucasians with first-degree family history of diabetes (relatives, n = 55) and those without family history (nonrelatives, n = 33). A significant correlation between the BMI and insulin response (area under the curve [AUC] during the 2-h period) was seen in nonrelatives (r = 0.68, P < 0.0001) but not in the relatives (r = 0.12, P = 0.37). Multivariate analysis revealed that obesity (BMI) was the primary determinant of insulin response in nonrelatives (P < 0.001), whereas among the relatives, BMI had no significant impact (P = 0.28). Thus, these distinctions between the relatives and nonrelatives remained after adjusting for glucose level, age, and gender. Among first-degree relatives, the commonly observed association between BMI and insulin response is lost, and hyperinsulinemia is present even in the absence of obesity. First-degree family history of diabetes may confer insulin resistance that is independent of obesity. Alternatively, this could suggest a pathological regulation of an obesity-insulin feedback loop, e.g., a defective recognition of adiposity.

Relationship of generalized and regional adiposity to insulin sensitivity in men with NIDDM.

Abdominal obesity, particularly excess intraperitoneal fat, is considered to play a major role in causing insulin resistance and NIDDM. To determine if NIDDM patients accumulate excess intraperitoneal fat, and whether this contributes significantly to their insulin resistance, 31 men with mild NIDDM with a wide range of adiposity were compared with 39 nondiabetic, control subjects for insulin sensitivity (measured using euglycemic-hyperinsulinemic clamp technique with [3-3H]glucose turnover) and total and regional adiposity (assessed by hydrodensitometry and by measuring subcutaneous abdominal, intraperitoneal, and retroperitoneal fat masses using magnetic resonance imaging [MRI], and truncal and peripheral skinfold thicknesses using calipers). MRI analysis revealed that intraperitoneal fat was not increased in NIDDM patients compared with control subjects; in both groups it averaged 11% of total body fat. NIDDM patients, however, had increased truncal-to-peripheral skinfolds thickness ratios. In NIDDM patients, as in control subjects, amounts of truncal subcutaneous fat showed a stronger correlation with glucose disposal rate than intraperitoneal or retroperitoneal fat; however, NIDDM patients were more insulin resistant at every level of total or regional adiposity. Further, no particular influence of excess intraperitoneal fat on hepatic insulin sensitivity was noted. We conclude that NIDDM patients do not have excess intraperitoneal fat, but that their fat distribution favors more truncal and less peripheral subcutaneous fat. Moreover, for each level of total and regional adiposity, NIDDM patients have a heightened state of insulin resistance.

Effect of statin therapy on remnant lipoprotein cholesterol levels in patients with combined hyperlipidemia.

Clinical trials with statins have demonstrated significant reductions in cardiovascular events. Remnant lipoproteins are independent predictors of cardiovascular events. Because of the paucity of data on the effect of statins on remnant lipoproteins, we tested the effect of pravastatin, simvastatin, and atorvastatin on remnant lipoprotein cholesterol (RLP-C) levels in a randomized crossover study in patients with combined hyperlipidemia. After a 6-week diet phase, patients (n=22) were randomized to pravastatin (40 mg/d), simvastatin (20 mg/d), or atorvastatin (10 mg/d) for 6 weeks, with a 3-week washout between each drug. All 3 drugs significantly decreased total and low density lipoprotein (LDL) cholesterol (P<0.001). Mean reduction in LDL cholesterol with pravastatin, simvastatin, and atorvastatin was 21%, 29%, and 32%, respectively. None of the drugs affected high density lipoprotein cholesterol levels. Median levels of triglycerides were significantly reduced with simvastatin (26%, P=0.001) and atorvastatin (24%, P=0.0001) but not with pravastatin (9%, P=0.18). Non-high density lipoprotein cholesterol decreased significantly with all 3 statins (20%, 29%, and 32% with pravastatin, simvastatin, and atorvastatin, respectively; P<0.001). Median RLP-C levels were significantly reduced with simvastatin (6%, P<0.05) and atorvastatin (25.9%, P<0.001) but not with pravastatin (2.9%, P=0.58). Thus, atorvastatin and simvastatin, in addition to reducing LDL cholesterol and triglyceride levels, significantly reduced RLP-C levels. This could be another potential mechanism to explain their cardiovascular benefits.

Sustained-release sodium fluoride in the treatment of the elderly with established osteoporosis.

BACKGROUND: We ascertained the safety and efficacy of fluoride in augmenting spinal bone mass and reducing spinal fractures in older women with established osteoporosis. We compared a combination of sustained-release sodium fluoride, calcium citrate, and cholecalciferol (SR-NaF group) with calcium and cholecalciferol alone (control group). METHODS: Eighty-five ambulatory women aged 65 years or older with 1 or more nontraumatic vertebral compression fractures were enrolled in a 42-month randomized, double-blind, placebo-controlled trial. Primary outcome measures were vertebral fracture rate, bone mass, and safety. RESULTS: The vertebral fracture rate determined by means of computer assistance in the SR-NaF group was significantly lower than that in the control group (relative risk [RR], 0.32; 95% confidence interval [CI], 0.14-0.73; P =.007). Results of visual adjudicated inspection also confirmed a significant reduction in fracture rate (RR, 0.40; 95% CI, 0.17-0.95; P =.04). Bone mineral density in L2 through L4 increased significantly from baseline in the SR-NaF group by 5.4% (95% CI, 2.7%-8.2%; P<.001), and by 3.2% in the control group (95% CI, 0.8%-5.6%; P =.01). The between-group differences in bone mineral density were not significant. The femoral neck and total hip bone mineral density remained stable in the SR-NaF group and was not significantly different from that of the control group. There were no significant differences in adverse effects between groups. CONCLUSION: The SR-NaF group significantly decreased the risk for vertebral fractures and increased spinal bone mass without reducing bone mass at the femoral neck and total hip.

Alkali absorption and citrate excretion in calcium nephrolithiasis.

The role of net gastrointestinal (GI) alkali absorption in the development of hypocitraturia was investigated. The net GI absorption of alkali was estimated from the difference between simple urinary cations (Ca, Mg, Na, and K) and anions (Cl and P). In 131 normal subjects, the 24 h urinary citrate was positively correlated with the net GI absorption of alkali (r = 0.49, p < 0.001). In 11 patients with distal renal tubular acidosis (RTA), urinary citrate excretion was subnormal relative to net GI alkali absorption, with data from most patients residing outside the 95% confidence ellipse described for normal subjects. However, the normal relationship between urinary citrate and net absorbed alkali was maintained in 11 patients with chronic diarrheal syndrome (CDS) and in 124 stone-forming patients devoid of RTA or CDS, half of whom had "idiopathic" hypocitraturia. The 18 stone-forming patients without RTA or CDS received potassium citrate (30-60 mEq/day). Both urinary citrate and net GI alkali absorption increased, yielding a significantly positive correlation (r = 0.62, p < 0.0001), with the slope indistinguishable from that of normal subjects. Thus, urinary citrate was normally dependent on the net GI absorption of alkali. This dependence was less marked in RTA, confirming the renal origin of hypocitraturia. However, the normal dependence was maintained in CDS and in idiopathic hypocitraturia, suggesting that reduced citrate excretion was largely dietary in origin as a result of low net alkali absorption (from a probable relative deficiency of vegetables and fruits or a relative excess of animal proteins).

Comparison of nonrandomized trials with slow-release sodium fluoride with a randomized placebo-controlled trial in postmenopausal osteoporosis.

The results of slow-release sodium fluoride (SR-NaF) treatment in two nonrandomized trials involving 65 patients with postmenopausal osteoporosis from the primary site and 121 patients from collaborative sites were compared with those obtained from 54 treated patients and 56 patients taking placebo from a randomized controlled trial. Spinal fracture data were analyzed separately in mild to moderate bone loss of lumbar spine (baseline L2-L4 bone density [BD] > or = 65% young normal) and in severe bone loss (BD < 65%). Since demographic and fracture data were similar among fluoride-treated patients from the three trials at each stratum of bone loss, their data were combined. In mild to moderate bone loss, SR-NaF treatment in the combined group virtually eliminated new spinal fractures with 96.6% of patients remaining fracture-free. The Fluoride group had a markedly lower individual vertebral fracture rate (0.025 vs. 0.188/patient year, p = 0.0001) and group vertebral fracture rate (0.029 vs. 0.175/patient year, relative risk [RR] 0.12, p = 0.0001) than the Placebo group. In severe bone loss, the combined treated group had a significantly lower new spinal fracture rate than the Placebo group, although the differences were not as marked (group vertebral fracture rate of 0.150 vs. 0.276/patient year, RR 0.54, p = 0.03). In the combined fluoride-treated group, the L2-L4 bone mass rose by 4-6%/year for 4 years, and the femoral neck BD increased by 1-2%/year during first 2 years. The radial shaft BD did not change. The Placebo group did not show a change in bone mass at any site. The prevalence (percentage) of patients with related gastrointestinal side effects and nonvertebral fracture rates did not differ significantly between the combined SR-NaF group and the Placebo group (hip fracture rate of 0.0045/patient year in SR-NaF and 0.0053/patient year in Placebo; appendicular fracture other than hip (see text) rate of 0.0193/patient year in SR-NaF and 0.0159/patient year in Placebo). A subgroup analysis showed a low baseline L2-L4 BD, high prevalent spinal fractures, and reduced body weight to be important determinants of the development of spinal fracture during SR-NaF treatment. Concomitant medications (estrogen, vitamin D, thiazide and thyroid hormone) were not independent predictors of the spinal fracture risk. Only 17% of fluoride-treated patients were nonresponders (new spinal fractures or a fall/no change in L2-L4 bone mass). Thus, the effects of SR-NaF treatment on the spinal fracture rate from nonrandomized trials were similar to those of the treated group of the randomized trial but different from those of the Placebo group. The similarity of response of nonrandomized trials with that of the randomized controlled trial and the resultant combined analysis further validate the efficacy and safety of SR-NaF in the treatment of postmenopausal osteoporosis.

Essential hypertension is associated with decreased insulin clearance and insulin resistance.

Essential hypertension is associated with multiple metabolic abnormalities, among them, hyperinsulinemia. This hyperinsulinemia is attributed to the presence of decreased insulin sensitivity (insulin resistance) with consequent compensatory insulin secretion. We tested the hypothesis that decreased insulin clearance is present in hypertensive subjects and contributes to hyperinsulinemia independently of the degree of insulin resistance. Seventy-five subjects were studied (48 hypertensive and 27 normotensive). Both groups were comparable in terms of age, body fat content, waist-to-hip ratio, and sex distribution. A primed continuous insulin infusion at 40 mU/m2 per minute was performed. Glucose was maintained at baseline levels with the euglycemic clamp technique. Hypertensive subjects were characterized by decreased insulin sensitivity (insulin-mediated glucose uptake: 5.14 +/- 0.28 versus 7.26 +/- 0.61 mg glucose/kg fat-free mass per minute, hypertensive versus normotensive, P = .002), increased insulin levels during the insulin infusions (804 +/- 36 versus 510 +/- 38 pmol/L, hypertensive versus normotensive, P < .001), and decreased insulin metabolic clearance rate (328 +/- 15 versus 521 +/- 30 mL/min per meter squared, hypertensive versus normotensive, P < .001). In an ANCOVA (including sex, degree of obesity, waist-to-hip ratio, and insulin sensitivity as covariates) the differences in insulin metabolic clearance rate between normotensive and hypertensive subjects remained highly significant (P < .001). Insulin metabolic clearance rate was significantly associated with fasting insulin levels. We conclude that essential hypertension is independently associated with decreased insulin metabolic clearance rate in addition to insulin resistance. A low insulin metabolic clearance rate may be a contributory factor to the hyperinsulinemia observed in essential hypertension.

Ambulatory evaluation of nephrolithiasis: an update of a 1980 protocol.

Evaluations of 1,270 patients with recurrent nephrolithiasis in an outpatient setting were analyzed for the purpose of updating the classification of nephrolithiasis. All but 4% had abnormal urinary biochemistry that placed them into one or more of 20 etiologic categories. A single diagnosis was documented in 41.3% of patients. The remaining 58.7% had more than one diagnosis. Hypercalciuric calcium (Ca) nephrolithiasis, encountered in 60.9% of patients, comprised six variants--absorptive hypercalciuria Type I and II, renal hypercalciuria, primary hyperparathyroidism, and unclassified hypercalciuria (renal phosphate leak and fasting hypercalciuria). Hyperuricosuria Ca nephrolithiasis (HUCN) and gouty diathesis (GD) accounted for 35.8% and 10.0% of patients, respectively. Distinguishing features were hyperuricosuria and normal urinary pH in HUCN, and normal urinary uric acid and low urinary pH (< 5.5) in GD. Hyperoxaluric Ca nephrolithiasis, occurring in 8.1% of patients, was subdivided into enteric, primary, and dietary variants. Hypocitraturic Ca nephrolithiasis affected 28% of patients in its idiopathic variant. Many of these patients' problems were probably dietary in origin, while some could have had incomplete renal tubular acidosis. Hypocitraturia due to renal tubular acidosis or chronic diarrheal syndrome affected only 3.3% of patients. Hypomagnesiuric Ca nephrolithiasis, infection stones, and cystinuria were uncommon, accounting for 6.8%, 5.9%, and 0.9% of patients, respectively. The acquired problem of low urine volume (< 1 L/d) was found in 15.3% of patients. The remaining 3.5% of patients were difficult to classify despite the presence of abnormal urinary biochemistry.