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Background IgA nephropathy (IGAN) rarely can present as a crescent and progressive form leading to end-stage renal disease (ESRD) in a short period of time. Recurrence of IGAN after kidney transplantation is frequent, and complement components such as C3, C4d, and C5 seem to be involved. We present a case of a young male patient with ESRD caused by rapidly progressive IGAN and who demonstrated rapid recurrence of crescentic IGAN after kidney donation. Case Report In September 2014, a 28-year-old male patient was hospitalized due to IGAN with 60% of crescents. Cyclophosphamide, steroids, and plasmapheresis did not prevent ESRD. After 8 months of peritoneal dialysis, the patient received a blood group–compatible living donor kidney from his 57-year-old mother. Immunosuppression consisted of tacrolimus, mycophenolic acid, and steroids without induction therapy. Acute graft failure occurred 2 months later, and graft biopsy results revealed recurrence of crescentic IGAN. Cyclophosphamide was added to tacrolimus and steroid treatment, but graft function could not be restored despite viable kidney tissue in repeated biopsy specimens. Rescue therapy with 4 single doses of eculizumab was introduced while hemodialysis had already been initiated. After a cumulative dose of 1800 mg of eculizumab, kidney function did not recover. Conclusions In this case, eculizumab was not effective in treating IGAN recurrence after transplantation. Therapy was started late when hemodialysis had already been initiated; an earlier start of therapy might be more effective. [ABSTRACT FROM AUTHOR]

Background Nocardia is a genus of gram-positive Actinomycetes that are ubiquitous in decaying organic material, soil, and water. Some Nocardia species can infect humans, mainly by airborne transmission. Several reports describe disseminated infections, which are rare and mostly affect strongly immunocompromised patients because intact T-cell–mediated immunity is the major protective mechanism. Case Report We report a case of disseminated pulmonary, cerebral, and cutaneous infection with Nocardia farcinica in a 66-year-old kidney transplant recipient treated with low-dose triple immunosuppression. The patient was initially admitted because of severe hyponatremia and pneumonia with radiologic signs of pleural effusion. The infectious agent was isolated when cutaneous lesions developed. Oral trimethoprim/sulfamethoxazole treatment led to severe hyponatremia; therefore, long-term treatment with parenteral amikacin and minocycline was initiated. After 7 months of consistent intravenous treatment, the lesions completely resolved and treatment was stopped, against some expert suggestions. The patient had remained free of relapse at the time of writing. Conclusions Disseminated Nocardia infection in immunocompromised patients is a rare but life-threatening disease. Owing to its infrequency, the variety of clinical patterns, antimicrobial resistance, and often fatal complications of standardized therapy, the diagnosis and treatment of this infection remain challenging and protracted. [ABSTRACT FROM AUTHOR]

Highlights: [•] Multicomponent geothermometry approach is coupled with numerical optimization. [•] Allows reconstruction the deep fluid composition using water analyses from multiple locations. [•] Application of this method to the Dixie Valley geothermal field suggests the presence of two separate reservoirs. [•] Impact of fluid re-equilibration on temperature estimations is investigated with reactive transport modeling. [•] Promising approach to evaluate geothermal reservoir temperatures in an integrated manner. [Copyright &y& Elsevier]

BACKGROUND: In the general population, C-reactive protein (CRP) in addition to low-density lipoprotein (LDL) cholesterol level is useful in predicting cardiovascular events. In hemodialysis patients, the additive value is unknown. The association between LDL cholesterol level and outcome previously was suggested to be inverse and confounded by inflammation. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 1,255 hemodialysis patients with type 2 diabetes mellitus randomly assigned to atorvastatin versus placebo in the German Diabetes Dialysis Study. PREDICTORS: Baseline LDL cholesterol level. OUTCOMES & MEASUREMENTS: Combined vascular end point (cardiac death, myocardial infarction, and stroke), mortality, myocardial infarction, sudden death, and stroke. RESULTS: During 4 years, 465 combined vascular events, 612 deaths, 160 sudden deaths, 200 myocardial infarctions, and 99 strokes occurred. Median LDL cholesterol level was 123 mg/dL. LDL cholesterol level (millimoles per liter and quartiles) was not predictive of outcome. This was analyzed further in patients with and without inflammation. In patients with inflammation (CRP level > 5 mg/L), the adjusted relative risk of combined vascular events was 29% greater compared with those without inflammation and a low LDL cholesterol level (LDL cholesterol 123mg/dL), 1.29, with 95% CI, 0.99 to 1.69). Similar results were found for all-cause death (HR(LDL123mg/dL), 1.48 [95% CI, 1.16 to 1.88]), sudden death (HR(LDL123mg/dL), 1.66 [95% CI, 1.01 to 2.75]), and myocardial infarction (HR(LDL123mg/dL), 1.54 [95% CI, 0.99 to 2.38]). In patients without inflammation, the respective risks did not differ significantly between patients with varying LDL cholesterol levels. However, there was a trend toward an increased risk of myocardial infarction (HR(LDL>123mg/dL), 1.45 [95% CI, 0.95 to 2.21]) in patients with high compared with low LDL cholesterol levels. P values for the interaction between CRP and LDL cholesterol levels were 0.9 (composite vascular end point), 0.5 (mortality), 0.9 (sudden death), 0.09 (stroke), and 0.2 (myocardial infarction). LIMITATIONS: Selected patient cohort, post hoc analysis. CONCLUSION: Because CRP level more than LDL cholesterol level determined outcome, the value of regular LDL cholesterol measurements in long-term hemodialysis patients with type 2 diabetes needs reassessment. [ABSTRACT FROM AUTHOR]

BACKGROUND: Obesity is a risk factor for loss of kidney function in the general population, but it is unknown whether it proceeds to affect residual kidney function when patients require dialysis. Our aim was to study the effects of body mass index (BMI) on decline in kidney function and risk to develop anuria after initiation of dialysis therapy. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 1,271 incident dialysis patients from 38 centers in The Netherlands participating in the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) between 1997 and 2006. PREDICTOR: BMI assessed at 3 months after the initiation of dialysis therapy (baseline) and categorized into 4 groups: less than 20, 20 or greater to 25, 25 or greater to 30, and 30 or greater kg/m(2). OUTCOMES & MEASUREMENTS: The decrease in measured glomerular filtration rate (mGFR) was determined by means of linear mixed models and adjusted for age, sex, primary kidney disease, dialysis modality, smoking, cardiovascular disease, and normalized protein nitrogen appearance and additionally for proteinuria, blood pressure, and baseline mGFR. Cox regression analysis was used to calculate hazard ratios for the development of anuria. RESULTS: Patients had a mean age of 59 +/- 15 years, BMI of 24.8 +/- 4.1 kg/m(2), and mGFR of 4.7 +/- 3.3 mL/min. During 18 months of follow-up, the decrease in mGFR in patients with normal weight was 1.2 mL/min/y (95% confidence interval [CI], 0.7 to 1.6). Compared with those values, adjusted losses of mGFR were 0.4 mL/min/y (95% CI, 0.02 to 0.8) greater for overweight and 1.2 mL/min/y (95% CI, 0.5 to 1.8) greater for obese patients. In contrast, the decrease in underweight patients was 0.6 mL/min/y (-0.1 to 1.3) less. Anuria occurred in 297 patients; the risk was similar among BMI groups after adjustment for confounders and baseline diuresis. LIMITATIONS: Patients with missing BMI or mGFR values at baseline were excluded. CONCLUSION: Obesity is a strong risk factor for the decline in kidney function after initiation of dialysis therapy. Whether obese dialysis patients might benefit from a healthy weight reduction needs to be studied further. Copyright © 2009 National Kidney Foundation, Inc. [ABSTRACT FROM AUTHOR]

BACKGROUND: Effects of dialyzer membrane characteristics on morbidity and mortality are highly controversial. METHODS: Post hoc, we analyzed data from the German Diabetes and Dialysis Study that evaluated atorvastatin in high-risk patients. Four groups were identified being constantly dialyzed with high-flux synthetic (n = 241), low-flux synthetic (n = 247), low-flux semisynthetic (n = 119), or cellulosic low-flux membranes (n = 41). Two end points were investigated: (1) a cardiovascular end point consisting of cardiac death, nonfatal myocardial infarction, and stroke and (2) death. RESULTS: After 4 years of follow-up, adjusted multivariate relative risks (RRs) were calculated. The RR to reach a cardiovascular end point was greater for patients dialyzed with cellulosic low-flux (RR, 2.33; 95% confidence interval [CI], 1.38 to 3.94; P = 0.002), low-flux semisynthetic (RR, 1.92; 95% CI, 1.35 to 2.73; P = 0.0003), or low-flux synthetic membranes (RR, 1.35; 95% CI, 0.99 to 1.85; P = 0.06) than for those treated with high-flux synthetic dialyzers. The likelihood to die was greater with cellulosic low-flux (RR, 4.14; 95% CI, 2.79 to 6.15; P < 0.0001), low-flux semisynthetic (RR, 2.24; 95% CI, 1.66 to 3.02; P < 0.0001), and low-flux synthetic membranes (RR, 1.59; 95% CI, 1.22 to 2.07; P = 0.0006) than with high-flux synthetic membranes. With respect to low-flux synthetic membranes, RRs of mortality for patients using cellulosic low-flux and low-flux semisynthetic membranes were 161% (RR, 2.61; 95% CI, 1.80 to 3.79; P < 0.0001) and 41% (RR, 1.41; 95% CI, 1.07 to 1.86; P = 0.016) greater. Cellulosic low-flux membrane use was associated with an 85% (RR, 1.85; 95% CI, 1.24 to 2.76; P = 0.0025) greater RR of death than low-flux semisynthetic membranes. CONCLUSION: These data suggest that biocompatibility and permeability may impact on death and cardiovascular events in hemodialysis patients with type 2 diabetes mellitus. Copyright © 2007 by the National Kidney Foundation, Inc. [ABSTRACT FROM AUTHOR]

Objective: Because angiogenesis is considered essential for tumor growth and the development of metastasis, we assessed the correlation of microvessel density with overall survival in patients with clinical stage IB carcinoma of the uterine cervix.Study Design: Histologic slides were immunostained for factor VIII-related antigen. Microvessel density was determined within each tumor by enumeration under a light microscope at 200x magnification and an examination area of 0.25 mm2. The Cox proportional hazards model was used for multivariate analysis.Results: In 166 patients with stage IB cervical cancer the 5-year survival was as follows: 89.7% in 102 patients whose tumors had a microvessel density < or =20/field, and 63.0% in 64 patients whose tumors had a microvessel density >20/field (log rank p < 0.0001). In the multivariate Cox model microvessel density, lymph node involvement, tumor size, and the application of radiation therapy remained independent prognostic factors for survival, whereas lymphatic vascular space involvement failed to retain a significant value.Conclusion: High microvessel density adversely influences patients' survival in clinical stage IB cervical cancer and identifies patients with negative nodes at risk for relapse. [ABSTRACT FROM AUTHOR]

Introduction Data suggest an additional role of T cells in antibody-mediated rejections. In 2001 a protocol for AB0-incompatible kidney transplantation based on B-cell–depleting anti–CD20 antibody rituximab, antigen-specific blood group IgG immunoadsorption, intravenous immunoglobulins, and triple immunosuppression was introduced in Europe, which used induction therapy with the use of interleukin-2 receptor antibody (IL2-RA) basiliximab. We used thymoglobulin in AB0-incompatible patients as induction in the face of high immunologic risk. Methods We retrospectively evaluated a cohort of 9 AB0i living donation (LD) recipients from 2011 to 2014. Desensitization included blood group–specific immunoadsorption. Eighteen AB0-compatible LD recipients receiving induction therapy with thymoglobulin served as control subjects. Another control group consisted of 18 AB0-compatible LD recipients receiving basiliximab. Follow-up was 24 months. We captured graft function by estimating glomerular filtration rate (eGFR by Modification of Diet in Renal Disease formula), rejection episodes, and bacterial and viral infections. Results All patients experienced immediate graft function. No significant or clinical differences were observed regarding graft function, rejection rates, or infections between the groups, although there seemed to be slightly higher cytomegalovirus infection rates due to preemptive therapy strategy. Conclusions Thymoglobulin appears to be similar in safety and efficacy to IL-2-antagonists in AB0i kidney transplantation. [ABSTRACT FROM AUTHOR]

Lipid parameters are altered in the earliest stages of primary kidney disease, some even when measured glomerular filtration rate (GFR) is still normal. The main problem is that routinely measured lipid parameters are deceivingly normal except low high-density lipoprotein (HDL) and moderately elevated triglycerides (TGs) (>150 mg per 100 ml). Behind this unimpressive spectrum, serious anomalies are hidden: increased very low-density lipoprotein (VLDL) and chylomicron remnants, accumulation of delipidated small dense low-density lipoprotein (LDL), post translational modification of lipoproteins, abnormal concentrations of Lp(a) and nonprotective HDL. A routine parameter with some predictive value is the concentration of non-HDL cholesterol. Several of these abnormal lipoprotein particles stimulate cellular free oxygen radical formation which in turn induce inflammation and impact on endothelial function.A bone of contention is the indication for treatment with statins in endstage renal disease. Poor survival is paradoxically predicted by low cholesterol. This appears to be the result of confounding by microinflammation. One controlled interventional study in hemodialysed type 2 diabetics, the 4-D study, failed to show a significant benefit on the primary cardiovascular endpoint. We discuss potential explanations for this 'negative' outcome and the implications for statin treatment.Kidney International (2008) 74, S24-S28. doi:10.1038/ki.2008.520 [ABSTRACT FROM AUTHOR]

In studies on the effects of therapy (or other interventions), the randomized controlled trial (RCT) is an almost unbeatable standard in clinical research. The value of RCTs leaves unabated the valuable contributions of observational studies to medicine. This paper discusses some limitations of RCTs providing examples where these are not possible, inappropriate, inadequate, or unnecessary. Thereafter, it focuses on observational studies and gives a number of examples of studies on etiology, diagnosis, prognosis, and adverse effects, where observational designs have provided answers to research questions that could not have been answered by RCTs. Strengths and weaknesses of the different observational study designs are discussed. Finally, it is concluded that both observational studies and RCTs fulfill a complementary and valuable role in nephrology.Kidney International (2007) 72, 671–675; doi:10.1038/sj.ki.5002397; published online 27 June 2007 [ABSTRACT FROM AUTHOR]

About 20% of the German population have a migration background which might influence prevalence of preventable cardiovascular risk factors (CVRF). We report data of the prospective Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression (STAAB) cohort study investigating a representative sample of inhabitants of the City of Würzburg, Germany, aged 30 to 79 years. Individuals without migration background were defined as follows: German as native language, no other native language, and/or born in Germany. All other participants were defined as individuals with migration background. Of 2473 subjects (51% female, mean age 54 ± 12 years), 291 (12%) reported a migration background: n = 107 (37%) from a country within the EU, n = 117 (40%) from Russia, and n = 67 (23%) from other countries. Prevalence of hypertension, atherosclerotic disease, and diabetes mellitus was similar in individuals with and without migration background. By contrast, prevalence of obesity and metabolic syndrome was significantly higher in individuals with migration background, with the least favourable profile apparent in individuals from Russia (individuals without vs. with migration background: obesity 19 vs. 24%, p < 0.05; odds ratio: EU: 1.6, Russia: 2.2*, other countries: 0.6; metabolic syndrome 18 vs. 21%, p < 0.05; odds ratio: EU: 1.2, Russia: 1.7*, other countries: 1.5; * p < 0.05). Individuals with migration background in Germany might exhibit a higher CVRF burden due to a higher prevalence of obesity and metabolic syndrome. Strategies for primary prevention of heart failure may benefit from deliberately considering the migration background. • In a representative sample of the population of Wuerzburg, Germany, 12% of participants reported a migration background • Prevalence of hypertension, atherosclerotic disease, and diabetes was equal to individuals without migration background • By contrast, prevalence of obesity and metabolic syndrome was significantly higher in individuals with migration background • Individuals from Russia revealed the least favourable profile of cardiovascular risk factors [ABSTRACT FROM AUTHOR]

The recent research findings concerning syndromes of muscle wasting, malnutrition, and inflammation in individuals with chronic kidney disease (CKD) or acute kidney injury (AKI) have led to a need for new terminology. To address this need, the International Society of Renal Nutrition and Metabolism (ISRNM) convened an expert panel to review and develop standard terminologies and definitions related to wasting, cachexia, malnutrition, and inflammation in CKD and AKI. The ISRNM expert panel recommends the term ‘protein–energy wasting’ for loss of body protein mass and fuel reserves. ‘Kidney disease wasting’ refers to the occurrence of protein–energy wasting in CKD or AKI regardless of the cause. Cachexia is a severe form of protein–energy wasting that occurs infrequently in kidney disease. Protein–energy wasting is diagnosed if three characteristics are present (low serum levels of albumin, transthyretin, or cholesterol), reduced body mass (low or reduced body or fat mass or weight loss with reduced intake of protein and energy), and reduced muscle mass (muscle wasting or sarcopenia, reduced mid-arm muscle circumference). The kidney disease wasting is divided into two main categories of CKD- and AKI-associated protein–energy wasting. Measures of chronic inflammation or other developing tests can be useful clues for the existence of protein–energy wasting but do not define protein–energy wasting. Clinical staging and potential treatment strategies for protein–energy wasting are to be developed in the future.Kidney International (2008) 73, 391–398; doi:10.1038/sj.ki.5002585; published online 19 December 2007 [ABSTRACT FROM AUTHOR]

The quality of a clinical study depends on internal and external factors. Studies have internal validity when, random error apart, reported differences between exposed and unexposed individuals can be attributed only to the exposure under investigation. Internal validity may be affected by bias, that is, by any systematic error that occurs in the design or in the conduction of a clinical research. Here we focus on two major categories of bias: selection bias and information bias. We describe three types of selection biases (incidence-prevalence bias, loss-to-follow-up bias, and publication bias) and a series of information biases (i.e. misclassification bias—recall bias, interviewer bias, observer bias, and regression dilution bias—and lead-time bias).Kidney International (2008) 73, 148–153; doi:10.1038/sj.ki.5002648; published online 31 October 2007 [ABSTRACT FROM AUTHOR]

The purpose of this paper is to discuss whether the randomized clinical trial (RCT) is indeed the gold standard among epidemiological studies. This paper illustrates to what extent different study designs may contribute to the answer of the following therapeutic research question based on a study of Wanner et al.: ‘Is the use of a statin associated to less cardiac mortality in patients with type 2 diabetes mellitus who receive hemodialysis?’ If a therapeutic study is feasible, like the research question of the clinical example, the RCT is almost unbeatable: the problems that may occur in the other study designs do not exist or to a lesser extent using an RCT. The main advantage of an RCT is that the randomization procedure helps to prevent selection bias by the clinician by breaking the link between the clinician's therapy prescription and the patient's prognosis. Within observational studies, however, selection by the clinician may occur, and, even after adjustment for potential confounders in the statistical analysis, it may not be possible to make a fair comparison between the groups. Usually, results from observational studies are needed to come to a hypothesis that can subsequently be tested within an RCT. Moreover, observational data are most often more useful than RCTs for non-therapeutic studies.Kidney International (2007) 72, 539–542; doi:10.1038/sj.ki.5002354; published online 27 June 2007 [ABSTRACT FROM AUTHOR]

Considerable variation in grading systems used to rate the strength of guideline recommendations and the quality of the supporting evidence in Nephrology highlights the need for a uniform, internationally accepted, rigorous system. In 2004, Kidney Disease: Improving Global Outcomes (KDIGO) commissioned a methods expert group to recommend an approach for grading in future nephrology guidelines. This position statement by KDIGO recommends adopting the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach for the grading of evidence and guidelines on interventions. The GRADE approach appraises systematic reviews of the benefits and harms of an intervention to determine its net health benefit. The system considers the design, quality, and quantity of studies as well as the consistency and directness of findings when grading the quality of evidence. The strength of the recommendation builds on the quality of the evidence and additional considerations including costs. Adaptations of the GRADE approach are presented to address some issues pertinent to the field of nephrology, including (1) the need to extrapolate from studies performed predominantly in patients without kidney disease, and (2) the need to use qualitative summaries of effects when it is not feasible to quantitatively summarize them. Further refinement of the system will be required for grading of evidence on questions other than those related to intervention effects, such as diagnostic accuracy and prognosis.Kidney International (2006) 70, 2058–2065. doi:10.1038/sj.ki.5001875; published online 27 September 2006 [ABSTRACT FROM AUTHOR]

The present study evaluated the evolution of cardiac morphology, function, and late enhancement as a noninvasive marker of myocardial fibrosis, and their inter-relation during enzyme replacement therapy in patients with Fabry's disease using magnetic resonance imaging and color Doppler myocardial imaging. Late enhancement, which was present in up to 50% of patients, was associated with increased left ventricular mass, the failure of a significant regression of hypertrophy during enzyme replacement therapy, and worse segmental myocardial function. Late enhancement may predict the effect of enzyme replacement therapy on left ventricular mass and cardiac function. [ABSTRACT FROM AUTHOR]

Enzyme replacement therapy (ERT) with recombinant human α-galactosidase A (r-hαGalA) enhances microvascular globotriaosylceramide clearance and improves clinical symptoms in patients with Fabry disease. We evaluated whether these effects are translated into a long-term benefit of kidney and heart function. We did a single center, prospective, open label study in 26 patients with Fabry disease (one early death, follow-up in 25 patients). r-α-GalA was administered in a dosage of 1 mg/kg body weight every second week. The effect of therapy on clinical end points (death, cardiac and cerebrovascular event, renal failure), cardiac and renal function monitored by Doppler echocardiography, 99Tc-GFR, and proteinuria was investigated. After a mean treatment time of 23±8 months, nine patients experienced 12 end points, including two deaths. All end points occurred in patients with impaired renal function (n=16; GFR 71±17 ml/min/1.73 m2). Despite ERT, renal function deteriorated to 60±23 ml/min/1.73 m2 (P=0.04) and left ventricular posterior wall thickness (PWT) did not change (14.0±2.1 vs 13.4±2.3 mm). In contrast, patients without impairment of renal function (n=9) had a more favorable outcome (no clinical events; GFR 115±18 vs 102±14 ml/min/1.73 m2, NS; PWT 11.7±1 and 10.7±0.7 mm, P=0.04). Proteinuria remained unchanged (1.34±0.94 vs 1.01±0.97 g/day, n=10). Patients with impaired renal function have a less favorable outcome and may develop cardiovascular and renal end points despite ERT.Kidney International (2006) 69, 1216–1221. doi:10.1038/sj.ki.5000208; published online 22 February 2006 [ABSTRACT FROM AUTHOR]

Smoking as a risk factor for end-stage renal failure in men with primary renal disease. Background. It is not known whether smoking increases the risk of end-stage renal failure (ESRF) in patients with primary renal disease. Methods . We performed a retrospective multicenter case-control study including 582 patients from nine centers in Germany, Italy and Austria. The diseases investigated were IgA glomerulonephritis (IgA-GN) as a model of inflammatory renal disease and autosomal dominant polycystic kidney disease (ADPKD) as a model of non-inflammatory renal disease. Cases were patients who had progressed to ESRF and controls were patients who were not in ESRF, that is, whose serum-creatinine failed to progress to >3 mg/dl during the observation period and who did not require renal replacement therapy. Matching for renal disease (IgA-GN, ADPKD), gender, age at renal death and region of residence resulted in 102 individually matched pairs (IgA-GN N = 54, ADPKD N = 48). Multiple conditional logistic regression was used to estimate adjusted odds ratios for independent tobacco effects. Results . In men (matched pairs: IgA-GN N = 44, ADPKD N = 28), a significant dose-dependent increase of the risk to progress to ESRF was found (non-adjusted). The baseline risk was defined as <5 pack-years (PY): (i ) 5 to 15 PY, odds ratio 3.5 (95% CI 1.3 to 9.6), P = 0.017; (ii ) >15 PY = 5.8 (2.0 to 17), P = 0.001. Systolic blood pressure, ACE inhibitor treatment and age at diagnosis emerged as potential confounders. After adjustment, the risk for ESRF in men with >5 PY was highly increased for patients without ACE inhibitor treatment [10.1 (2.3 to 45), P = 0.002] but not with ACE inhibitor treatment [1.4 (0.3 to 7.1), P = 0.65]. Conclusion . Smoking increases the risk of ESRF in men with inflammatory and non-inflammatory renal disease. [ABSTRACT FROM AUTHOR]

Epidemiological studies aim at assessing the relationship between exposures and outcomes. Clinicians are interested in knowing not only whether a link between a given exposure (e.g. smoking) and a certain outcome (e.g. myocardial infarction) is statistically significant, but also the magnitude of this relationship. The 'measures of effect' are indexes that summarize the strength of the link between exposures and outcomes and can help the clinician in taking decisions in every day clinical practice. In epidemiological studies, the effect of exposure can be measured both in relative and absolute terms. The risk ratio, the incidence rate ratio, and the odds ratio are relative measures of effect. Risk difference is an absolute measure of effect and it is calculated by subtracting the risk of the outcome in exposed individuals from that of unexposed. [ABSTRACT FROM AUTHOR]