Measuring health-related quality of life in patients with conservatively managed stage 5 chronic kidney disease: limitations of the Medical Outcomes Study Short Form 36: SF-36.

PURPOSE: Chronic kidney disease (CKD) negatively affects health-related quality of life (HRQoL), which is often measured using the Medical Outcomes Study Short Form 36 (SF-36) questionnaire. However, the adequacy of SF-36 in this population has not been reported. We aimed to determine floor and ceiling effects and responsiveness to change of SF-36 in patients with conservatively managed stage 5 CKD. METHODS: SF-36 data were collected prospectively. Floor and ceiling effects were estimated for each SF-36 scale and summary measure based on raw scores. The minimal clinically important difference (MCID) was estimated using a combination of anchor-based and distribution-based methods. Responsiveness to change was assessed by comparing MCID for each scale and summary measure to its smallest detectable change. RESULTS: SF-36 data were available for 73 of the 74 study participants. Using baseline data, floor and/or ceiling effects were detected for 3 of the 8 SF-36 scales. The anchor-based estimation of MCID based on differences in baseline functional status yielded the most reliable results. For the physical component summary, MCID was estimated at 5.7 points. Whilst the two SF-36 summary measures were responsive to change and free of floor and/or ceiling effects, six of the eight scales were not. CONCLUSIONS: This small study of patients with conservatively managed stage 5 CKD found that only the summary measures of SF-36 and 2 of its 8 scales can be used to assess changes in HRQoL over time. These findings suggest that in this population, alternative HRQoL assessment tools should be considered for future studies.

Increased risk for atherosclerosis of various macrophage scavenger receptor 1 alleles.

AIMS: Macrophage scavenger receptor 1 (MSR1) mediates the uptake of modified low density lipoprotein (LDL)-cholesterol. The significance of MSR1 in atherosclerosis development in animal models is uncertain. In this study we sought to determine the significance of MSR1 polymorphisms in its encoding gene in susceptibility to atherosclerosis. METHODS: We genotyped three polymorphic sites in the MSR1 gene including a 3-bp "TTA" insertion-deletion in intron 7 (rs3036811, Indel 7), an intron 5 SNP (rs33959637, IVS5-59), and a missense coding single nucleotide polymorphism (SNP) in exon 6 (rs3747531, P275A) in 136 nondiabetic Ashkenazi men under age 55 years (mean = 47.3 +/- 4.8 years) undergoing coronary angiography. Assessment of coronary disease was done by the number of segments with stenosis greater than 20% (coronary artery narrowing greater than 20% [CAGE > 20%]), greater than 50% (CAGE > 50%), and total number of diseased vessels. Linear regression modeling was used to define associations between atherosclerotic burden and MSR1 SNPs and haplotypes. RESULTS: Significant associations were noted between IVS5-59 and number of diseased vessels (p = 0.009) and CAGE > 20% (p = 0.017), which remained significant upon controlling for age, cholesterol level, hypertension, and smoking. CONCLUSION: This study demonstrates an association between MSR1 polymorphisms and atherosclerosis, suggesting that atherosclerotic risk associated with classic risk factors may be modified by MSR1 polymorphisms. These findings point to a significant role of MSR1 in atherosclerosis.

Mutations in LPIN1 cause recurrent acute myoglobinuria in childhood.

Recurrent episodes of life-threatening myoglobinuria in childhood are caused by inborn errors of glycogenolysis, mitochondrial fatty acid beta-oxidation, and oxidative phosphorylation. Nonetheless, approximately half of the patients do not suffer from a defect in any of these pathways. Using homozygosity mapping, we identified six deleterious mutations in the LPIN1 gene in patients who presented at 2-7 years of age with recurrent, massive rhabdomyolysis. The LPIN1 gene encodes the muscle-specific phosphatidic acid phosphatase, a key enzyme in triglyceride and membrane phospholipid biosynthesis. Of six individuals who developed statin-induced myopathy, one was a carrier for Glu769Gly, a pathogenic mutation in the LPIN1 gene. Analysis of phospholipid content disclosed accumulation of phosphatidic acid and lysophospholipids in muscle tissue of the more severe genotype. Mutations in the LPIN1 gene cause recurrent rhabdomyolysis in childhood, and a carrier state may predispose for statin-induced myopathy.

SREBP-2 and SCAP isoforms and risk of early onset myocardial infarction.

BACKGROUND: Cholesterol metabolism is mediated, in part, by the sterol-regulatory element binding proteins (SREBPs) that are activated by a SREBP cleavage-activating protein (SCAP). We examined whether coding variations in the interacting domains of both genes, are related to early-onset MI risk in a population-based case-control study from western Washington State. METHODS: Cases were 257 women, aged 18-59 years, and 320 men, aged 18-49 years, with first acute non-fatal MI; controls were 353 women and 311 men, similar in age, identified from the community who had no history of clinical CHD or stroke. Genotyping of the SREBF-2 G1784C polymorphism (SREBP-2-595A/G isoforms), and the SCAP A2386G polymorphism (SCAP-796I/V isoforms), were performed. RESULTS: After adjustment for age and race, the SREBP-2-595A isoform was associated with increased MI risk among men (OR=1.63, 95% CI=1.26-2.12). In contrast, there was little evidence for an association among women in a multiplicative model. However, compared to SREBP-2-595G homozygotes, homozygote women for the SREBP-2-595A isoform were at nearly two-fold increased risk (OR=1.95, 95% CI=1.07-3.54). Overall, SCAP genotypes were neither associated with MI in men nor in women. However, in men, SCAP genotypes were found to modify the association between SREBF-2 and MI (p-value for interaction=0.01). CONCLUSION: The SREBP-2-595A isoform was associated with an increased risk of early-onset MI in U.S. men. The SCAP polymorphism appeared to modify the associations of SREBF-2 genotype with MI risk among men. These novel findings require confirmation in other populations.

Aspirin withdrawal prior to invasive medical procedures: a strategy based on thromboembolic and bleeding risk stratification.

BACKGROUND: The management of aspirin therapy before an invasive procedure poses a frequent clinical dilemma due to uncertainty regarding bleeding versus thromboembolic risks associated with continuation or withdrawal of the drug. There are no evidence-based data to refer to. OBJECTIVES: To assess the opinions of internal medicine physicians regarding aspirin therapy prior to an invasive procedure. METHODS: A questionnaire presenting nine hypothetical cases with different combinations of bleeding and thromboembolic risk was given to physicians in an internal medicine division during a personal interview. For each case the participants had to choose between withdrawal of aspirin prior to an invasive procedure, continuation of aspirin, or substitution of low molecular weight heparin for aspirin. RESULTS: Sixty-one physicians participated in the survey. For a patient with low thromboembolic risk, 77% (95% confidence interval 65.3-86.3%), 95% (87.2-98.7%) and 97% (89.6-99.5%) of physicians elected to discontinue aspirin prior to a low, intermediate or high bleeding risk procedure, respectively. For intermediate risk patients, 23% (95% CI 13.7-34.7%), 59% (46.4-70.8%) and 74% (61.7-83.6%) would discontinue aspirin prior to a low, intermediate or high risk procedure, and 5% (95% CI 1.3-12.8%), 23% (13.7-34.7%) and 18% (9.9-29.2%) would substitute LMWH for aspirin. For a patient with high thromboembolic risk, 1.6% (95% CI 0.08-7.8%), 11.5% (5.2-21.4%) and 18% (9.9-29.2%) recommended discontinuing aspirin prior to a low, intermediate or high risk procedure, respectively. In these situations, 18% (95% CI 9.9-29.2%), 53% (40.0-64.7%) and 57% (44.8-69.3%), respectively, would substitute LMWH for aspirin. CONCLUSIONS: The results of the current investigation may help practicing physicians to decide whether to discontinue aspirin therapy prior to invasive procedures. The possible use of LMWH to replace aspirin as suggested here should be further evaluated in a controlled clinical study.