Yasemin Yavuz

Diagnostic value of serum cystatin C for evaluation of hepatorenal syndrome

BACKGROUND The evaluation of renal function in patients with decompensated cirrhosis is important for prognosis, dosage assessment of potentially nephrotoxic drugs and recognition of changes in glomerular filtration rate (GFR) to decide paracentesis and diuretic therapy. Patients with many different disorders of hepatic function can present with various abnormalities of renal function in the absence of other known causes of renal failure which has been called hepatorenal syndrome (HRS). Some reports have pointed out that serum creatinine levels frequently failed to rise above normal levels even when glomerular filtration rate (GFR) is very low in cirrhotic patients with hepatorenal syndrome. The aim of this study was to determine if estimation of serum cystatin C could replace creatinine clearance in routine GFR determinations for patients with cirrhosis. METHODS Serum cystatin C, creatinine clearance (Clcr), and 99mTc-DTPA clearance were determined in 26 patients with cirrhosis. According to Child-Pughs classification, 21 patients were in group C and 5 were in Group B. RESULTS Pearson correlation analyses showed that correlation between serum cystatin C and 99mTc-DTPA clearance was r=-0.522, p=0.006, between serum creatinine and 99mTc-DTPA was r=-0.373, p=0.06. The results of our study demonstrated that neither serum creatinine nor creatinine clearance (Clcr) were good indicators of hepatorenal syndrome because the mean value for Clcr was found to be higher than Tc-DTPA clearance, and there was no correlation between these two parameters (r=0.059). Additionally, the mean value of serum creatinine was found to be within the normal range, whereas the mean DTPA clearance level was lower than normal range. CONCLUSIONS This finding could be explained by the fact that cirrhotic patients with poor nutrition may have decreased protein intake, low muscle mass and lack of converting capacity of creatine to creatinine. Thus, we suggest that serum cystatin C assay, which has good analytical performance, could replace or at least be added to creatinine measurement for GFR assessment in patients with cirrhosis.

Concurrent Generation of Ordinal and Normal Data

The use of joint models that are capable of handling different data types is becoming increasingly popular in biopharmaceutical practice. Evaluation of various statistical techniques that have been developed for mixed data in simulated environments requires joint generation of multiple variables. In this article, we propose a unified framework for concurrently simulating ordinal and normal data given the marginal characteristics and correlation structure. We illustrate our technique in two simulation settings where we use artificial data as well as real depression score data from psychiatric research, demonstrating negligibly small deviations between the specified and empirically computed quantities.

Global Alignment and Proportion (GAP) Score: Development and Validation of a New Method of Analyzing Spinopelvic Alignment to Predict Mechanical Complications After Adult Spinal Deformity Surgery.

Background: The restoration of normal sagittal alignment is a critical goal in adult spinal deformity surgery to achieve favorable outcomes and prevent mechanical complications. Schwab sagittal modifiers have been accepted as targets for appropriate alignment, but addressing these targets does not always prevent high mechanical complication or revision rates. This may be because the linear absolute numerical parameters do not cover the whole pelvic incidence spectrum and the distribution of lordosis, pelvic anteversion, and negative malalignment are not considered as potential causes of failure. The aim of the present study was to develop and validate a score based on pelvic-incidence-based proportional parameters to better predict mechanical complications. Methods: Two hundred and twenty-two patients (168 women and 54 men) followed for ≥2 years after posterior fusion at ≥4 levels were included in the study. The mean age (and standard deviation) was 52.2 ± 19.3 years (range, 18 to 84 years), and the mean duration of follow-up was 28.8 ± 8.2 months (range, 24 to 62 months). The global alignment and proportion (GAP) score was developed and validated in groups of patients randomly assigned to derivation (n = 148, 66.7%) and validation (n = 74, 33.3%) cohorts. GAP score parameters were relative pelvic version (the measured minus the ideal sacral slope), relative lumbar lordosis (the measured minus the ideal lumbar lordosis), lordosis distribution index (the L4-S1 lordosis divided by the L1-S1 lordosis multiplied by 100), relative spinopelvic alignment (the measured minus the ideal global tilt), and an age factor. Proximal and distal junctional kyphosis and/or failure, rod breakage, and other implant-related complications were considered mechanical complications. The predictive accuracy of the GAP score was analyzed using receiver operating characteristic (ROC) analyses. Associations between GAP categories and mechanical complications and revisions were analyzed using Cochran-Armitage tests. Results: In the validation cohort, 32 patients (43%) experienced mechanical complications and 17 (23%) underwent mechanical revision. The area under curve for the GAP score predicting mechanical complications was 0.92 (standard error [SE] = 0.034, p < 0.001, 95% [confidence interval [CI] = 0.85 to 0.98). Postoperatively, patients with a proportioned spinopelvic state according to the GAP score had a mechanical complication rate of 6% while those with a moderately or severely disproportioned spinopelvic state had rates of 47% and 95%, respectively. Conclusions: The GAP score is a new pelvic-incidence-based proportional method of analyzing the sagittal plane that predicts mechanical complications in patients undergoing surgery for adult spinal deformity. Setting surgical goals according to the GAP score may decrease the prevalence of mechanical complications.

Multiple Regression Analysis of Factors Affecting Health-Related Quality of Life in Adult Spinal Deformity.

BACKGROUND Previous studies demonstrated the adult spinal deformity (ASD) population is heterogeneous. Multiple parameters may affect health-related quality of life (HRQL). AIM To understand the ranking of parameters affecting HRQL in ASD using multiple regression analysis. PATIENTS AND METHODS A total of 483 patients enrolled in a prospective multicenter ASD database from the population. Multiple regression analysis was performed for Scoliosis Research Society-22 (SRS-22) and Oswestry Disability Index (ODI) separately. Initially proposed primary variables of diagnosis (highest correlation), age, lordosis gap (L gap), and coronal curve location were regressed for each response variable (SRS-22 and ODI) univariately. Age and L gap could not be used together because of high colinearity. Coronal curve location was removed owing to an insignificant correlation. Two initial models were considered per response, consisting of diagnosis and age in one and diagnosis and L gap in the other. The rest of the potentially predictive variables were introduced in these models one at a time. Final models were evaluated using stepwise automatic model selection. RESULTS For ODI, body mass index (BMI), gender, and sagittal and spinopelvic parameters were in the basic model but only BMI and gender in the model with L gap and only gender in the model with age were highly predictive. For SRS-22, a large number of parameters were in the basic model but BMI, gender, coronal balance, lordosis curve, and sagittal vertical axis in the model with L gap and only gender in the model with age were highly predictive. Coronal curve location was not significantly predictive in any model. CONCLUSIONS These findings reiterate the importance of patient diagnosis, age, and/or the amount of lordosis as the most important factors affecting HRQL in ASD. Gender, BMI, and sagittal vertical axis appear to be consistently important co-variables whereas coronal balance and magnitude of L curves may also be important in SRS-22. These may aid in better understanding the problem in ASD and may be useful in future classifications.

Reliability and Validity of the Adapted Turkish Version of the Early-onset Scoliosis-24-Item Questionnaire (EOSQ-24).

Introduction: Early-onset scoliosis (EOS) can have negative effects on the developing thorax, lungs, and quality of life in general. Children with EOS can face various health problems and require recurring hospitalization and surgeries. Radiographic parameters are insufficient to evaluate the severity and efficacy of treatment in EOS. Early-onset Scoliosis Questionnaire (EOSQ)-24 questionnaire is a new instrument developed for this specific age group. To date, reliability of this questionnaire has not yet been interrogated in wide patient groups from different cultures. The aim of this study was to evaluate the validity and reliability of culturally adapted Turkish version of the EOSQ-24. Methods: Forward translation and back translation of the English version of the EOSQ-24 was done, and all steps for cross-cultural adaptation process were performed properly by an expert committee. Turkish version of the EOSQ-24 and Child Health Questionnaire-Parent Form-50 (CHQ-PF-50) were applied to 61 (24 male, 37 female) EOS patients. The average age of these patients was 9.1±3.1 years (0.4 to 14.3 y), and 50 of them had undergone surgical treatment. Data quality was assessed by mean, median, percentage of missing data, and extent of ceiling and floor effects. Reliability was assessed by internal consistency using Cronbach’s &agr; and item-total correlations. The construct validity was evaluated by comparing the results of the EOSQ-24 with the Turkish version of the CHQ-PF-50. Subgroup analyses were applied for sex, diagnosis, treated/untreated, mobilization ability, and complications. Results: The item response to the EOSQ-24 was high with a small number of missing answers (1.6% to 3.3%). Of the 24 items, 22 were evenly distributed. This resulted in a floor effect in 0% to 21.7% of patients, and a ceiling effect in 1.6% to 68.3%. The calculated Cronbach’s &agr; for the 24-item scale was 0.909, indicating excellent reliability. Construct validity showed that high correlations between the EOSQ and the CHQ by means of similar domains. Correlation coefficient was between 0.348 and 0.688 (P=0.0001). Subgroup analyses also showed significant difference in treated/untreated patients (P=0.032) and mobilization ability (P=0.001). Discussion: The Turkish adaptation of the EOSQ-24 exhibits favorable psychometric properties and excellent reliability, validating its use in this population. Level of Evidence: Level III—diagnostic study.

Decision analysis to identify the ideal treatment for adult spinal deformity: What is the impact of complications on treatment outcomes?

Objective The aim of this study was to analyze the impact of treatment complications on outcomes in adult spinal deformity (ASD) using a decision analysis (DA) model. Methods The study included 535 ASD patients (371 with non-surgical (NS) and 164 with surgical (S) treatment) from an international multicentre database of ASD patients. DA was structured in two main steps; 1) Baseline analysis (Assessing the probabilities of outcomes, Assessing the values of preference -utilities-, Combining information on probability and utility and assigning the quality adjusted life expectancy (QALE) for each treatment) and 2) Sensitivity analysis. Complications were analyzed as life threatening (LT) and nonlife threatening (NLT) and their probabilities were calculated from the database as well as a thorough literature review. Outcomes were analyzed as improvement, no change and deterioration. Death/complete paralysis was considered as a separate category. Results All 535 patients were analyzed in regard to complications. Overall, there were 78 NLT and 12 LT complications and 3 death/paralysis. Surgical treatment offered significantly higher chances of clinical improvement but also was significantly more prone to complications (31.7% vs. 11.1%, p < 0.001). Conclusion Surgical treatment of ASD is more likely to cause complications compared to NS treatment. On the other hand, surgery has been shown to provide a higher likelihood of improvement in HRQoL scores. So, the decision on the type of treatment in ASD needs to take both chances of improvement and burden associated with S or NS treatments and better be arrived by the active participation of patients and physicians equipped with the present information. Level of evidence Level II, Decision analysis.

Risk factors associated with local recurrence after curative resection for rectal cancer

A retrospective study was conducted to identify the factors related to locoregional recurrence in patients who underwent curative resections for primary rectal cancer between January 1986 and April 1994 at Ankara Oncology Hospital in Turkey. A step-wise logistic regression analysis was applied for 116 patients who had complete follow-up. Age, sex, macroscopic size of the lesion, tumor location in the rectum as determined by the distance from the anal verge, obstruction at presentation, tumor histology, lymphatic invasion, venous invasion, stage according to TNM classification, differentiation of the tumor, surgical treatment modality, radical abdominopelvic lymphadenectomy (RAPL), and blood transfusion were used as the clinico-pathologic variables. Locoregional recurrent disease was found after a mean follow-up period of 52 months in 28 (24.1%) patients, while the median recurrence-free period was 12 months. Univariate analysis demonstrated that age, disease stage, tumor grade, obstruction, RAPL, blood transfusion, and venous and lymphatic invasion were significant risk factors (P<0.05); however, using multivariate analysis, an increased risk for the development of locoregional recurrence was found to be associated with: age (P=0.0052), stage (P=0.0379), blood transfusion (P=0.0276), obstruction (P=0.0035), and RAPL (P=0.0069).

Relative lumbar lordosis and lordosis distribution index: individualized pelvic incidence–based proportional parameters that quantify lumbar lordosis more precisely than the concept of pelvic incidence minus lumbar lordosis

OBJECTIVE The subtraction of lumbar lordosis (LL) from the pelvic incidence (PI) offers an estimate of the LL required for a given PI value. Relative LL (RLL) and the lordosis distribution index (LDI) are PI-based individualized measures. RLL quantifies the magnitude of lordosis relative to the ideal lordosis as defined by the magnitude of PI. LDI defines the magnitude of lower arc lordosis in proportion to total lordosis. The aim of this study was to compare RLL and PI - LL for their ability to predict postoperative complications and their correlations with health-related quality of life (HRQOL) scores. METHODS Inclusion criteria were ≥ 4 levels of fusion and ≥ 2 years of follow-up. Mechanical complications were proximal junctional kyphosis/proximal junctional failure, distal junctional kyphosis/distal junctional failure, rod breakage, and implant-related complications. Correlations between PI - LL, RLL, PI, and HRQOL were analyzed using the Pearson correlation coefficient. Mechanical complication rates in PI - LL, RLL, LDI, RLL, and LDI interpreted together, and RLL subgroups for each PI - LL category were compared using chi-square tests and the exact test. Predictive models for mechanical complications with RLL and PI - LL were analyzed using binomial logistic regressions. RESULTS Two hundred twenty-two patients (168 women, 54 men) were included. The mean age was 52.2 ± 19.3 years (range 18-84 years). The mean follow-up was 28.8 ± 8.2 months (range 24-62 months). There was a significant correlation between PI - LL and PI (r = 0.441, p < 0.001), threatening the use of PI - LL to quantify spinopelvic mismatch for different PI values. RLL was not correlated with PI (r = -0.093, p > 0.05); therefore, it was able to quantify divergence from ideal lordosis for all PI values. Compared with PI - LL, RLL had stronger correlations with HRQOL scores (p < 0.05). Discrimination performance was better for the model with RLL than for PI - LL. The agreement between RLL and PI - LL was high (κ = 0.943, p < 0.001), moderate (κ = 0.455, p < 0.001), and poor (κ = -0.154, p = 0.343), respectively, for large, average, and small PI sizes. When analyzed by RLL, each PI - LL category was further divided into distinct groups of patients who had different mechanical complication rates (p < 0.001). CONCLUSIONS Using the formula of PI - LL may be insufficient to quantify normolordosis for the whole spectrum of PI values when applied as an absolute numeric value in conjunction with previously reported population-based average thresholds of 10° and 20°. Schwab PI - LL groups were found to constitute an inhomogeneous group of patients. RLL offers an individualized quantification of LL for all PI sizes. Compared with PI - LL, RLL showed a greater association with both mechanical complications and HRQOL. The use of RLL and LDI together, instead of PI - LL, for surgical planning may result in lower mechanical complication rates and better long-term HRQOL.