Comparisons of the mean differences and standardized mean differences for continuous outcome measures on the same scale

When conducting systematic reviews and meta-analyses of continuous outcomes, the mean differences (MDs) and standardized mean differences (SMDs) are 2 commonly used choices for effect measures. The SMDs are motivated by scenarios where studies collected in a systematic review do not report the continuous measures on the same scale. The standardization process transfers the MDs to be unit-free measures that can be synthesized across studies. As such, some evidence synthesis researchers tend to prefer the SMD over the MD. However, other researchers have concerns about the interpretability of the SMD. The standardization process could also yield additional heterogeneity between studies. In this paper, we use simulation studies to illustrate that, in a scenario where the continuous measures are on the same scale, the SMD could have considerably poorer performance compared with the MD in some cases. The simulations compare the MD and SMD in various settings, including cases where the normality assumption of continuous measures does not hold. We conclude that although the SMD remains useful for evidence synthesis of continuous measures on different scales, the SMD could have substantially greater biases, greater mean squared errors, and lower coverage probabilities of CIs than the MD. The MD is generally more robust to the violation of the normality assumption for continuous measures. In scenarios where continuous measures are inherently comparable or can be transformed to a common scale, the MD is the preferred choice for an effect measure.

Istaroxime for Patients with Acute Heart Failure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Istaroxime, an intravenous inotropic agent with a dual mechanism-increasing both cardiomyocyte contractility and relaxation-is a novel treatment for acute heart failure (AHF), the leading cause of morbidity and mortality in heart failure. We conducted a systematic review and meta-analysis that synthesized randomized controlled trials (RCTs), which were retrieved by systematically searching PubMed, Web of Science, SCOPUS, and Cochrane until 24 April 2023. We used a fixed-effect or random-effect model-according to heterogeneity-to pool dichotomous data using the risk ratio (RR) and continuous data using the mean difference (MD), with a 95% confidence interval (CI). We included three RCTs with a total of 300 patients. Istaroxime was significantly associated with an increased left ventricular ejection fraction (mL) (MD: 1.06, 95% CI: 0.29, 1.82; p = 0.007), stroke volume index (MD: 3.04, 95% CI: 2.41, 3.67; p = 0.00001), and cardiac index (L/min/m2) (MD: 0.18, 95% CI: 0.11, 025; p = 0.00001). Also, istaroxime was significantly associated with a decreased E/A ratio (MD: -0.39, 95% CI: -0.58, -0.19; p = 0.0001) and pulmonary artery systolic pressure (mmHg) (MD: 2.30, 95% CI: 3.20, 1.40; p = 0.00001). Istaroxime was significantly associated with increased systolic blood pressure (mmHg) (MD: 5.32, 95% CI: 2.28, 8.37; p = 0.0006) and decreased heart rate (bpm) (MD: -3.05, 95% CI: -5.27, -0.82; p = 0.007). Since istaroxime improved hemodynamic and echocardiographic parameters, it constitutes a promising strategy for AHF management. However, the current literature is limited to a small number of RCTs, warranting further large-scale phase III trials before clinical endorsement.

Anterior Fontanel Size Among Term Newborns: A Systematic Review and Meta-Analysis

Background: Anterior fontanel is an integral element of an infant craniofacial system. There are six fontanels in the newborn skull, namely anterior, posterior, two mastoid, and two sphenoid fontanels. The anterior fontanel is the largest, prominent, and most important for clinical evaluation. Sex, race, genetics, gestational age, and region are the principal factors that influence anterior fontanel size. There exist inconclusive findings on the size of anterior fontanel in newborns. Therefore, this systematic review and meta-analysis aimed to determine the pooled mean size of anterior fontanel among term newborns and to identify the pooled mean difference of anterior fontanel size between males and females.

Methods: PubMed/Medline, Google Scholar, Science Direct, JBI Library, embase, and Cochrane Library databases were systematically searched. All essential data were extracted using a standardized data extraction format. The heterogeneity across studies was assessed using the Cochrane Q test statistic, I² test statistic, and p-values. A fixed-effect model and random effect model were used to estimate the pooled mean size of anterior fontanel and the pooled mean difference between male newborns and female newborns, respectively. To deal with heterogeneity, sub-group analysis, meta-regression analysis, and sensitivity analysis were considered. JBI quality appraisal checklist was used to evaluate the quality of studies.

Results: In this meta-analysis, 8, 661 newborns were involved in twenty-six studies. Among studies, 13 conducted in Asia, 7 in Africa, 5 in America, and 1 in Europe. The pooled mean size of anterior fontanel was 2.58 cm (95% CI: 2.31, 2.85 cm). The pooled mean size of anterior fontanel for Asia, Africa, America, and Europe region was 2.49, 3.15, 2.35, and 2.01 cm, respectively. A statistically significant mean difference was detected between male and female newborns (D + L pooled MD = 0.15 cm, 95% CI: 0.02, 0.29 cm).

Conclusion: The pooled estimate of this review does provide the mean value of the anterior fontanel size in the newborns. There was a statistically significant mean fontanel size difference between male and female newborns. Therefore, male newborns had a significantly larger mean size than female newborns.

Novel empirical likelihood inference for the mean difference with right-censored data

This paper focuses on comparing two means and finding a confidence interval for the difference of two means with right-censored data using the empirical likelihood method combined with the independent and identically distributed random functions representation. In the literature, some early researchers proposed empirical link-based confidence intervals for the mean difference based on right-censored data using the synthetic data approach. However, their empirical log-likelihood ratio statistic has a scaled chi-squared distribution. To avoid the estimation of the scale parameter in constructing confidence intervals, we propose an empirical likelihood method based on the independent and identically distributed representation of Kaplan-Meier weights involved in the empirical likelihood ratio. We obtain the standard chi-squared distribution. We also apply the adjusted empirical likelihood to improve coverage accuracy for small samples. In addition, we investigate a new empirical likelihood method, the mean empirical likelihood, within the framework of our study. The performances of all the empirical likelihood methods are compared via extensive simulations. The proposed empirical likelihood-based confidence interval has better coverage accuracy than those from existing methods. Finally, our findings are illustrated with a real data set.

A Q statistic with constant weights for assessing heterogeneity in meta-analysis

The conventional Q statistic, using estimated inverse-variance (IV) weights, underlies a variety of problems in random-effects meta-analysis. In previous work on standardized mean difference and log-odds-ratio, we found superior performance with an estimator of the overall effect whose weights use only group-level sample sizes. The Q statistic with those weights has the form proposed by DerSimonian and Kacker. The distribution of this Q and the Q with IV weights must generally be approximated. We investigate approximations for those distributions, as a basis for testing and estimating the between-study variance (τ² ). A simulation study, with mean difference as the effect measure, provides a framework for assessing accuracy of the approximations, level and power of the tests, and bias in estimating τ² . Two examples illustrate estimation of τ² and the overall mean difference. Use of Q with sample-size-based weights and its exact distribution (available for mean difference and evaluated by Farebrother's algorithm) provides precise levels even for very small and unbalanced sample sizes. The corresponding estimator of τ² is almost unbiased for 10 or more small studies. This performance compares favorably with the extremely liberal behavior of the standard tests of heterogeneity and the largely biased estimators based on inverse-variance weights.

A Meta-Analysis of Blood Pressure Disparities Among Sexual Minority Men

Purpose: The aim was to review and summarize reports on three measures of elevated blood pressure (BP) among sexual minority men (encompassing men who have sex with men [MSM] and both men and women [MSMW]), using men who have sex with women (MSW) as the reference population. Methods: Crude prevalence rates were calculated, and a meta-analysis was conducted to summarize the likelihood of elevated BP history, antihypertensive medication use, and elevated BP above a cutoff value, as well as the mean differences (MDs) in systolic BP (SBP) and diastolic BP (DBP) measurements. We used random effects to generate estimates with their respective 95% confidence intervals (CIs); alpha was set at 0.05. Results: Studies (n = 20) were published between 2007 and 2018, mostly in the United States. The likelihood of elevated BP history was not statistically significantly higher among sexual minority men, except when the measurement of sexual orientation was multidimensional (odds ratio [OR] 1.41, 95% CI 1.12-1.78). The likelihood of antihypertensive medication use was only statistically significantly higher for men who self-identified as MSMW (OR 1.44, 95% CI 1.11-1.85). When elevated BP was determined through a set cutoff, MSM were less likely (OR 0.34, 95% CI 0.16-0.70), whereas MSMW were more likely (OR 2.25, 95% CI 1.54-3.28) to have elevated BP. Although there were no statistically significant findings in the MD for SBP, the MD for DBP among sexual minority men was significantly higher (MD 1.46, 95% CI 1.38-1.55 mmHg) than among the MSW comparison group. Conclusions: Sexual minority men classified using a multidimensional approach to sexual orientation had a significantly higher likelihood of elevated BP history. Using BP cutoffs yielded opposite effects in MSM and MSMW. Although SBP was not different compared to MSW, DBP-a marker of hypertension at earlier ages-was elevated among sexual minority men.

Sex Differences in Episodic Memory Variance

Men as a group have been shown to have larger variances than women in several areas pertaining to both biological and psychological traits, but no investigation has been performed in regard to episodic memory. We conducted an analysis on sex differences in episodic memory variance on 535 studies, representing 962,946 individuals, conducted between 1973 and 2013. Results showed that men had larger variances than women in verbal episodic memory tasks as well as episodic memory tasks having to do with spatial locations. Women, on the other hand, had larger variance than men for tasks involving remembering routes. These effects were for the most part small, and exploratory analyses suggest that they might come about, at least in part, because of measures not sufficiently controlled for ceiling effects. This means that the effects should be interpreted with caution and that further research on sex differences in episodic memory variance is needed.

Estimation in meta-analyses of mean difference and standardized mean difference

Methods for random‐effects meta‐analysis require an estimate of the between‐study variance, τ². The performance of estimators of τ² (measured by bias and coverage) affects their usefulness in assessing heterogeneity of study‐level effects and also the performance of related estimators of the overall effect. However, as we show, the performance of the methods varies widely among effect measures. For the effect measures mean difference (MD) and standardized MD (SMD), we use improved effect‐measure‐specific approximations to the expected value of Q for both MD and SMD to introduce two new methods of point estimation of τ² for MD (Welch‐type and corrected DerSimonian‐Laird) and one WT interval method. We also introduce one point estimator and one interval estimator for τ² in SMD. Extensive simulations compare our methods with four point estimators of τ² (the popular methods of DerSimonian‐Laird, restricted maximum likelihood, and Mandel and Paule, and the less‐familiar method of Jackson) and four interval estimators for τ² (profile likelihood, Q‐profile, Biggerstaff and Jackson, and Jackson). We also study related point and interval estimators of the overall effect, including an estimator whose weights use only study‐level sample sizes. We provide measure‐specific recommendations from our comprehensive simulation study and discuss an example.

Combining multiple imputation and bootstrap in the analysis of cost-effectiveness trial data

In healthcare cost-effectiveness analysis, probability distributions are typically skewed and missing data are frequent. Bootstrap and multiple imputation are well-established resampling methods for handling skewed and missing data. However, it is not clear how these techniques should be combined. This paper addresses combining multiple imputation and bootstrap to obtain confidence intervals of the mean difference in outcome for two independent treatment groups. We assessed statistical validity and efficiency of 10 candidate methods and applied these methods to a clinical data set. Single imputation nested in the bootstrap percentile method (with added noise to reflect the uncertainty of the imputation) emerged as the method with the best statistical properties. However, this method can require extensive computation times and the lack of standard software makes this method not accessible for a larger group of researchers. Using a standard unpaired t-test with standard multiple imputation without bootstrap appears to be a robust alternative with acceptable statistical performance for which standard multiple imputation software is available.

Tumor necrosis factor alpha is a promising circulating biomarker for the development of obstructive sleep apnea syndrome: a meta-analysis

Obstructive sleep apnea syndrome (OSAS) is a chronic inflammatory disorder. The relationship between tumor necrosis factor alpha (TNF-alpha) and OSAS has been widely evaluated, but the results thus far remain inconclusive. We thereby decided to quantify the changes of TNF-alpha between OSAS patients and controls by a meta-analysis. This study complies with the MOOSE guidelines. Two reviewers independently searched articles and abstracted relevant data. In total, 47 articles (59 studies) were analyzed, including 2857 OSAS patients and 2115 controls. Overall, OSAS patients had a significantly higher level of circulating TNF-alpha than controls (weighted mean difference [WMD]: 9.66 pg/mL, 95% confidence interval [CI]: 8.66 to 11.24, P<0.001), but with significant heterogeneity (I²: 99.7%). After adjusting for potential missing studies, the overall estimate was weakened but still significant (filled WMD: 2.63 pg/mL, 95% CI: 2.56 to 2.70, P<0.001). When studies were stratified by OSAS severity, the changes in circulating TNF-alpha between patients and controls increased gradually with the more severe grades of OSAS. In patients with mild, mild-to-moderate, moderate, moderate-to-severe and severe OSAS, circulating TNF-alpha was higher than respective controls by 0.99, 1.48. 7.79, 10.08 and 8.85 pg/mL, with significant heterogeneity (I²: 91.2%, 74.5%, 97.6%, 99.0% and 98.1%). In conclusion, our findings demonstrated that circulating TNF-alpha was significantly higher in OSAS patients than in controls, and this difference became more pronounced with the more severe grades of OSAS, indicating that TNF-alpha might be a promising circulating biomarker for the development of OSAS.

Minimal Clinically Important Differences for American Orthopaedic Foot & Ankle Society Score in Hallux Valgus Surgery

BACKGROUND

The American Orthopaedic Foot & Ankle Society (AOFAS) score is one of the most common and adapted outcome scales in hallux valgus surgery. However, AOFAS is predominantly physician based and not patient based. Although it may be straightforward to derive statistical significance, it may not equate to the true subjective benefit of the patient's experience. There is a paucity of literature defining MCID for AOFAS in hallux valgus surgery although it could have a great impact on the accuracy of analyzing surgical outcomes. Hence, the primary aim of this study was to define the Minimal Clinically Important Difference (MCID) for the AOFAS score in these patients, and the secondary aim was to correlate patients' demographics to the MCID.

METHODS

We conducted a retrospective cross-sectional study. A total of 446 patients were reviewed preoperatively and followed up for 2 years. An anchor question was asked 2 years postoperation: "How would you rate the overall results of your treatment for your foot and ankle condition?" (excellent, very good, good, fair, poor, terrible). The MCID was derived using 4 methods, 3 from an anchor-based approach and 1 from a distribution-based approach. Anchor-based approaches were (1) mean difference in 2-year AOFAS scores of patients who answered "good" versus "fair" based on the anchor question; (2) mean change of AOFAS score preoperatively and at 2-year follow-up in patients who answered good; (3) receiver operating characteristic (ROC) curves method, where the area under the curve (AUC) represented the likelihood that the scoring system would accurately discriminate these 2 groups of patients. The distribution-based approach used to calculate MCID was the effect size method. There were 405 (90.8%) females and 41 (9.2%) males. Mean age was 51.2 (standard deviation [SD] = 13) years, mean preoperative BMI was 24.2 (SD = 4.1).

RESULTS

Mean preoperative AOFAS score was 55.6 (SD = 16.8), with significant improvement to 85.7 (SD = 14.4) in 2 years ( P value < .001). There were no statistical differences between demographics or preoperative AOFAS scores of patients with good versus fair satisfaction levels. At 2 years, patients who had good satisfaction had higher AOFAS scores than fair satisfaction (83.9 vs 78.1, P < .001) and higher mean change (30.2 vs 22.3, P = .015). Mean change in AOFAS score in patients with good satisfaction was 30.2 (SD = 19.8). Mean difference in good versus fair satisfaction was 7.9. Using ROC analysis, the cut-off point is 29.0, with an area under the curve (AUC) of 0.62. Effect size method derived an MCID of 8.4 with a moderate effect size of 0.5. Multiple linear regression demonstrated increasing age (β = -0.129, CI = -0.245, -0.013, P = .030) and higher preoperative AOFAS score (β = -0.874, CI = -0.644, -0.081, P < .001) to significantly decrease the amount of change in the AOFAS score.

CONCLUSION

The MCID of AOFAS score in hallux valgus surgery was 7.9 to 30.2. The MCID can ensure clinical improvement from a patient's perspective and also aid in interpreting results from clinical trials and other studies.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Statistical methodology for estimating the mean difference in a meta-analysis without study-specific variance information

Statistical inference for analyzing the results from several independent studies on the same quantity of interest has been investigated frequently in recent decades. Typically, any meta-analytic inference requires that the quantity of interest is available from each study together with an estimate of its variability. The current work is motivated by a meta-analysis on comparing two treatments (thoracoscopic and open) of congenital lung malformations in young children. Quantities of interest include continuous end-points such as length of operation or number of chest tube days. As studies only report mean values (and no standard errors or confidence intervals), the question arises how meta-analytic inference can be developed. We suggest two methods to estimate study-specific variances in such a meta-analysis, where only sample means and sample sizes are available in the treatment arms. A general likelihood ratio test is derived for testing equality of variances in two groups. By means of simulation studies, the bias and estimated standard error of the overall mean difference from both methodologies are evaluated and compared with two existing approaches: complete study analysis only and partial variance information. The performance of the test is evaluated in terms of type I error. Additionally, we illustrate these methods in the meta-analysis on comparing thoracoscopic and open surgery for congenital lung malformations and in a meta-analysis on the change in renal function after kidney donation. Copyright © 2017 John Wiley & Sons, Ltd.

Trends in Iron, Zinc, and Vitamin A Status Biomarkers Among Colombian Children: Results From 2 Nationally Representative Surveys

BACKGROUND

Micronutrient deficiencies are still highly prevalent in countries undergoing the nutrition transition, but nationally representative data documenting their burden in children are exceedingly rare.

OBJECTIVE

To examine the distribution and recent trends in micronutrient status biomarkers of Colombian children.

METHODS

We compared the distributions of plasma ferritin, serum zinc, and vitamin A in Colombian children between 2005 and 2010 using 2 cross-sectional, nationally representative surveys overall and by categories of sociodemographic variables. Analysis for ferritin included boys and nonpregnant girls aged 1 to 17 years. Analyses for zinc and vitamin A included children aged 1 to 4 years.

RESULTS

The mean 2010 to 2005 differences in ferritin, zinc, and vitamin A were 2.5 µg/L (95% confidence interval [CI]: 1.3 to 3.7), -34.9 µg/dL (95% CI: -39.6 to -30.2), and -11.5 µg/dL (95% CI: -12.3 to -10.7), respectively, after adjusting for sociodemographic characteristics. These differences varied significantly by region of residence. In 2010, region of residence was a significant correlate for all 3 micronutrients. Other important correlates included age and maternal education for ferritin and body mass index-for-age Z score, maternal education, wealth index, food insecurity, and urbanicity for vitamin A.

CONCLUSIONS

Plasma ferritin was slightly higher in 2010 than in 2005, whereas serum zinc and vitamin A were substantially lower in 2010. In the absence of obvious causal explanations, it is uncertain whether this decline represents a worsening of micronutrient status in Colombian children or an artifact due to systematic laboratory or data management errors incurred in the surveys.

How effective are common medications: a perspective based on meta-analyses of major drugs

The vastness of clinical data and the progressing specialization of medical knowledge may lead to misinterpretation of medication efficacy. To show a realistic perspective on drug efficacy we present meta-analyses on some of the most commonly used pharmacological interventions. For each pharmacological intervention we present statistical indexes (absolute risk or response difference, percentage response ratio, mean difference, standardized mean difference) that are often used to represent efficacy. We found that some of the medications have relatively low effect sizes with only 11 out of 17 of them showing a minimal clinically important difference. Efficacy was often established based on surrogate outcomes and not the more relevant patient-oriented outcomes. As the interpretation of the efficacy of medication is complex, more training for physicians might be needed to get a more realistic view of drug efficacy. That could help prevent harmful overtreatment and reinforce an evidence-based, but personalized medicine.

Meta-analysis of absolute mean differences from randomised trials with treatment-related clustering associated with care providers

Nesting of patients within care providers in trials of physical and talking therapies creates an additional level within the design. The statistical implications of this are analogous to those of cluster randomised trials, except that the clustering effect may interact with treatment and can be restricted to one or more of the arms. The statistical model that is recommended at the trial level includes a random effect for the care provider but allows the provider and patient level variances to differ across arms. Evidence suggests that, while potentially important, such within-trial clustering effects have rarely been taken into account in trials and do not appear to have been considered in meta-analyses of these trials. This paper describes summary measures and individual-patient-data methods for meta-analysing absolute mean differences from randomised trials with two-level nested clustering effects, contrasting fixed and random effects meta-analysis models. It extends methods for incorporating trials with unequal variances and homogeneous clustering to allow for between-arm and between-trial heterogeneity in intra-class correlation coefficient estimates. The work is motivated by a meta-analysis of trials of counselling in primary care, where the control is no counselling and the outcome is the Beck Depression Inventory. Assuming equal counsellor intra-class correlation coefficients across trials, the recommended random-effects heteroscedastic model gave a pooled absolute mean difference of -2.53 (95% CI -5.33 to 0.27) using summary measures and -2.51 (95% CI -5.35 to 0.33) with the individual-patient-data. Pooled estimates were consistently below a minimally important clinical difference of four to five points on the Beck Depression Inventory.

Impact of cesarean section on placental transfusion and iron-related hematological indices in term neonates: a systematic review and meta-analysis

Evidence suggests that cesarean section is likely associated with a reduced placental transfusion and poor hematological status in neonates. However, clinical studies have reported somewhat inconsistent results. We conducted a systematic review and meta-analysis to examine whether cesarean section affects placental transfusion and iron-related hematological indices. Pubmed, Web of Science, ScienceDirect, and Ovid Databases were searched for relevant studies published before April 9, 2013. Mean differences between cesarean section and vaginal delivery in outcomes of interests (placental residual blood volume; hematocrit level, hemoglobin concentration, and erythrocyte count in cord/peripheral blood) were extracted and pooled using a random effects model. We identified 15 studies (n = 8477) eligible for the meta-analysis. Compared with neonates born vaginally, those born by cesarean section had a higher placental residual blood volume [weighted mean difference (WMD), 8.87 ml; 95% confidence interval (CI), 2.32 ml-15.43 ml]; a lower level of hematocrit (WMD, -2.91%; 95% CI, -4.16% to -1.65%), hemoglobin (WMD, -0.51 g/dL; 95% CI, -0.74 g/dL to -0.27 g/dL) and erythrocyte (WMD, -0.16 × 10(12)/L; 95% CI, -0.30 × 10(12)/L to -0.01 × 10(12)/L). Subgroup analysis showed that the WMD for hematocrit in neonate's peripheral blood (-6.94%; 95% CI, -9.15% to -4.73%) was substantially lower than that in cord blood (-1.75%; 95% CI, -2.82%, -0.68%) (P value for testing subgroup differences <0.001). In conclusion, cesarean section compared with vaginal delivery is associated with a reduced placental transfusion and poor iron-related hematologic indices in both cord and peripheral blood, indicating that neonates delivered by cesarean section might be more likely affected by iron-deficiency anemia in infancy.

Daily vs. intermittent inhaled corticosteroids for recurrent wheezing and mild persistent asthma: a systematic review with meta-analysis

BACKGROUND

Intermittent ICS treatment with SABA in response to symptoms, is an emerging strategy for control of mild-to-moderate asthma, and recurrent wheezing. This systematic revue compares the efficacy of daily vs. intermittent ICS among preschoolers, children and adults with persistent wheezing and mild to moderate stable persistent asthma.

METHODS

Systematic review of randomized, placebo-controlled trials with a minimum of 8 weeks of daily (daily ICS with rescue SABA during exacerbations) vs. intermittent ICS (ICS plus SABA at the onset of symptoms), were retrieved through different databases. Primary outcome was asthma exacerbations; secondary outcomes were pulmonary function tests, symptoms, days without symptoms, SABA use, corticosteroids use, days without rescue medication use, expired nitric oxide and serious adverse events.

RESULTS

Seven trials (1367 participants) met inclusion criteria there was no statistically significant difference in the rate of asthma exacerbations between those with daily vs. intermittent ICS (0.96; 95% CI: 0.86, 1.06, I(2) = 0%). In the sub-group analysis, no differences were seen in duration of studies, step-up strategy or age. However, compared to intermittent ICS, the daily ICS group had a significant increase in asthma-free days and non-significant decreases in rescue SABA use and exhaled nitric oxide measurement.

CONCLUSIONS

No significant differences between daily and intermittent ICS in reducing the incidence of asthma exacerbations was found. However, the daily ICS strategy was superior in many secondary outcomes. Therefore, this study suggests to not change daily for intermittent ICS use among preschoolers, children with persistent wheezing and adults with mild-to-moderate stable persistent asthma. International prospective register of systematic reviews http://www.crd.york.ac.uk/PROSPERO/ (CRD42012003228).

Laparoscopic pyelolithotomy compared to percutaneous nephrolithotomy as surgical management for large renal pelvic calculi: a meta-analysis. J Urol. 2013;190:888-893. [PMID: 23454154 DOI: 10.1016/j.juro.2013.02.092]

PURPOSE

We assessed the effectiveness and safety of laparoscopic pyelolithotomy and percutaneous nephrolithotomy as surgical management for solitary renal pelvic calculi larger than 2 cm.

MATERIALS AND METHODS

We searched PubMed®, EMBASE®, The Cochrane Library and the Web of Knowledge(SM) databases up to November 9, 2012 for relevant published studies. After data extraction and quality assessment, meta-analysis was performed using RevMan 5.1.

RESULTS

We identified 7 trials in a total of 176 and 187 patients treated with laparoscopic pyelolithotomy and percutaneous nephrolithotomy, respectively. Operative time and hospital stay were 50.62 minutes and 0.66 days shorter in the nephrolithotomy group (p <0.0001 and 0.04, respectively). Patients in the laparoscopic group benefited from a lesser decrease in hemoglobin (OR -1.00, 95% CI -1.77--0.23), less postoperative fever (OR 0.24, 95% CI 0.08-0.72), a lower incidence of bleeding (OR 0.29, 95% CI 0.10-0.85) and a higher stone-free rate (OR 4.85, 95% CI 1.59-14.82). Sensitivity analysis indicated that all results were stable except the stone-free rate showed no statistically significant difference between the 2 groups (OR 0.33, 95% CI 0.09-1.17). No publication bias was detected.

CONCLUSIONS

Current evidence suggests that laparoscopic pyelolithotomy and percutaneous nephrolithotomy are effective and safe for large renal pelvic calculi but laparoscopic pyelolithotomy seems to be more advantageous. However, given the inherent limitations of the included studies, results must be further confirmed in high quality randomized, controlled trials.