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Nevin Manimala Statistics

Calculating the power to examine treatment-covariate interactions when planning an individual participant data meta-analysis of randomized trials with a binary outcome

Stat Med. 2022 Aug 5. doi: 10.1002/sim.9538. Online ahead of print.

ABSTRACT

Before embarking on an individual participant data meta-analysis (IPDMA) project, researchers and funders need assurance it is worth their time and cost. This should include consideration of how many studies are promising their IPD and, given the characteristics of these studies, the power of an IPDMA including them. Here, we show how to estimate the power of a planned IPDMA of randomized trials to examine treatment-covariate interactions at the participant level (ie, treatment effect modifiers). We focus on a binary outcome with binary or continuous covariates, and propose a three-step approach, which assumes the true interaction size is common to all trials. In step one, the user must specify a minimally important interaction size and, for each trial separately (eg, as obtained from trial publications), the following aggregate data: the number of participants and events in control and treatment groups, the mean and SD for each continuous covariate, and the proportion of participants in each category for each binary covariate. This allows the variance of the interaction estimate to be calculated for each trial, using an analytic solution for Fisher’s information matrix from a logistic regression model. Step 2 calculates the variance of the summary interaction estimate from the planned IPDMA (equal to the inverse of the sum of the inverse trial variances from step 1), and step 3 calculates the corresponding power based on a two-sided Wald test. Stata and R code are provided, and two examples given for illustration. Extension to allow for between-study heterogeneity is also considered.

PMID:35932153 | DOI:10.1002/sim.9538

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Nevin Manimala Statistics

Comparison of HIV-related Ocular Involvement in HAART-naive and HAART-treated Patients

J Coll Physicians Surg Pak. 2022 Aug;32(8):1033-1036. doi: 10.29271/jcpsp.2022.08.1033.

ABSTRACT

OBJECTIVE: To compare the HIV-related ocular manifestations between HAART-naïve (Highly active antiretroviral therapy) and HAART-treated patients.

STUDY DESIGN: Observational (comparative) Study. Place and Duration of the Study: Department of Ophthalmology and Family Care Centre of Hayatabad Medical Complex, Peshawar, Pakistan, from October 2019 to July 2021.

METHODOLOGY: HIV-infected patients, who were receiving HAART treatment as well as HAART-naïve, were recruited. A complete ocular examination was performed to check for HIV-related ocular manifestations. Anterior and posterior segment findings were recorded and compared between the two groups.

RESULTS: Of the 80 participants (40 in each group), 62 (77.5%) were males and 18 (22.5) were females with no significant difference between the groups for either gender (p=1.0). A significant difference, between the two groups, was found in the mean duration (838.64 + 908.16 days) of HIV infection at the time of recruitment (p<0.001). HIV-related ocular manifestations were found in 6 (7.5%) with no statistically significant difference between the two groups (p=1.0). Similarly, the involvement of systemic co-infections was found in 6 (7.5%) with no statistically significant difference between the groups (p=0.675).

CONCLUSION: There was no difference in both groups when analysed for HIV-related ocular manifestations or systemic co-infections. The authors’ finding contradict with some of the previously published data. Therefore, it is recommended that further research should be carried out to reach definite conclusion.

KEY WORDS: HIV, Eye manifestations, Acquired immunodeficiency syndrome, Highly active antiretroviral therapy, HIV-related opportunistic infections, Pakistan.

PMID:35932128 | DOI:10.29271/jcpsp.2022.08.1033

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Nevin Manimala Statistics

Vasogenic Edema Pattern in Brain Metastasis

J Coll Physicians Surg Pak. 2022 Aug;32(8):1020-1025. doi: 10.29271/jcpsp.2022.08.1020.

ABSTRACT

OBJECTIVE: To determine the relationship of the presence and amount of vasogenic edema with origin, type, and grade of primary cancer.

STUDY DESIGN: Cross-sectional study.

PLACE AND DURATION OF STUDY: Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Radiology Clinic, Ankara, Turkey, from July 2017 to October 2021.

METHODOLOGY: Brain MRI scans of 292 patients were retrospectively evaluated. Age, gender, origin, type, and grade of primary cancer were determined. Metastasis type, and presence of vasogenic edema accompanying metastatic lesion were questioned. In cases of vasogenic edema accompanying metastatic lesions, the largest diameter of the vasogenic edema mass complex was measured in T2 sequences. In the contrast-enhanced series, the largest diameter of the metastatic lesion was measured, and the edema-mass ratio (EMR) was calculated by proportioning the diameter of the edema mass complex to the diameter of the mass.

RESULTS: The frequency of vasogenic edema was found higher in patients with lung cancer compared to other primaries. The EMR was found statistically significantly higher in patients with primary lung cancer (p=0.001). This was particularly evident in the adenocarcinoma group. In the patient group with primary breast cancer, EMR was found significantly lower in patients with invasive ductal carcinoma. (IDC→1.95±0.66 vs. Other→2.48±0.52, Z=-2.301, p=0.021).

CONCLUSION: The amount and presence of vasogenic edema in patients with brain metastases may differ according to the origin and type of primary tumour.

KEY WORDS: Brain edema, Metastatic disease, Magnetic resonance imaging.

PMID:35932126 | DOI:10.29271/jcpsp.2022.08.1020

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Nevin Manimala Statistics

Systemic Immune Inflammation Index as a Key Marker of Survival and Immune-related Adverse Events in Immune Checkpoint Inhibitor Therapy

J Coll Physicians Surg Pak. 2022 Aug;32(8):996-1003. doi: 10.29271/jcpsp.2022.08.996.

ABSTRACT

OBJECTIVE: To evaluate the prognostic significance of the new index designed by formulating neutrophil, lymphocyte, and platelet counts in patients with metastatic disease receiving immune checkpoint inhibitors (ICI) and its effect on the immune-related adverse events (irAEs).

STUDY DESIGN: Cohort study.

PLACE AND DURATION OF STUDY: Department of Medical Oncology, University of Manisa Celal Bayar, University of Aydin Adnan Menderes, and University of Ege, and Izmir Kent Hospital, Turkey, from January 2016 to April 2020.

METHODOLOGY: Patients with metastatic disease receiving ICI sufficient follow-up data were included. Patients, who had received treatment for a minimum of 3 months, were evaluated for the response. Systemic immune-inflammation index (SII) was calculated as neutrophil (/L) × (lymphocyte (/L) / platelet (/L). The cut-off value was determined by examining the area under the receiver operating characteristic (ROC) curve for the SII value. The endpoints of this study included overall survival (OS) and progression-free survival (PFS).

RESULTS: A total of 168, patients who received ICI in the metastatic stage, were evaluated. The OS of the patients with low SII scores was 110.8 months (95% CI, 88.2-133.5), while patients with high SII scores were 36.0 months (95% CI, 28.4-43.6) and reached statistical significance (p <0.001). The results of univariate (HR=3.376, 95% CI, 1.986-5.739, p<0.001 and multivariate (HR=2.792, 95% CI, 1.495-5.215, p=0.011) analyses were statistically significant as well.

CONCLUSION: The SII score in patients with metastatic disease receiving ICI was closely related to the prognosis. Patients with a high SII score are associated with a worse prognosis, these patients develop fewer irAEs.

KEY WORDS: Systemic immune inflammation index, Overall survival, Progression-free survival, İmmune checkpoint inhibitor, Pembrolizumab, Nivolumab.

PMID:35932122 | DOI:10.29271/jcpsp.2022.08.996

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Nevin Manimala Statistics

Flowcytometric Ratios of Immune Cells in the Prognosis and Staging of Acute Biliary Pancreatitis

J Coll Physicians Surg Pak. 2022 Aug;32(8):1004-1008. doi: 10.29271/jcpsp.2022.08.1004.

ABSTRACT

OBJECTIVE: To evaluate several lymphocyte subtypes with various parameters that can be applied easily and give fast results for their roles in evaluating the stage and prognosis of acute biliary pancreatitis.

STUDY DESIGN: Case-control study.

PLACE AND DURATION OF STUDY: The Emergency Department of Istanbul Training and Research Hospital, and Gaziosmanpasa Research and Training Hospital, Turkey, between June 2020 and April 2021.

METHODOLOGY: Patients, who admitted to the Emergency Department with acute pancreatitis and treated after hospitalisation, were included in the study. The patients were divided into three groups; mild, moderately severe and severe, according to the 2012 revised Atlanta classification. Hematocrit, creatinine, potassium, sodium values, and flow cytometry ratios of lymphocyte, monocyte, CD4+, CD8+, and regulatory T cells were measured and the difference between the groups were evaluated. Their results were compared with healthy volunteers.

RESULTS: A total of 53 persons including 40 with acute pancreatitis (14 mild, 14 moderately severe, and 12 in the severe pancreatitis groups) and 13 healthy volunteers, were included in the study. The average age of the studied participants was 50.9 ±13.42 years, 43.3% males and 56.7% females. Leukocyte values, lymphocyte rates, hematocrit rates, age, hospital staying duration, creatinine, potassium values, CD4+, and CD3+ lymphocyte rates were found to be different at a statistically significant level between the groups.

CONCLUSION: High leukocyte, low lymphocyte, high hematocrit, advanced age, elevated creatinine, elevated potassium, low CD4+ T lymphocyte, low CD3+ T lymphocyte, and low lymphocyte/monocyte ratio were identified as poor prognostic indicators.

KEY WORDS: Acute pancreatitis, Flow cytometry, Regulatory T cell, Atlanta.

PMID:35932123 | DOI:10.29271/jcpsp.2022.08.1004

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Nevin Manimala Statistics

Extrahepatic Biliary Tract Variations is an Effect for Acute Calculous Cholecystitis

J Coll Physicians Surg Pak. 2022 Aug;32(8):991-995. doi: 10.29271/jcpsp.2022.08.991.

ABSTRACT

OBJECTIVE: To evaluate the anatomy of the extrahepatic bile duct and to reveal its importance in the formation of acute calculous cholecystitis (ACC).

STUDY DESIGN: Case-control study.

PLACE AND DURATION OF STUDY: Department of General Surgery and Radiology, Kanuni Sultan Suleyman Training and Research Hospital of the University of Health Sciences, Turkey, between January 2016 and December 2021.

METHODOLOGY: The data of the patients treated with ACC were analysed on MRCP by an experienced radiologist. The patients were divided into two groups; asymptomatic gallstones (AsGS, control group) and ACC. The cystic duct, common hepatic duct, and common bile duct lengths and variations in cystic duct opening were measured. Receiver operating characteristics (ROC) analysis was conducted to define a cut-off value and compared categorical results of the two groups by Mann-Whitney U test.

RESULTS: One-hundred and seventy-three patients were analysed, one-hundred and seven were females, and 66 were males. The median age was 46 years in the AsGS group and 53 years in the ACC group. It was statistically significant that ACC had a higher median age value than AsGS (p=0.014). In the analysis of extrahepatic variations, cystic duct, common hepatic duct, and common bile duct length, were statistically longer in the calculous cholecystitis group (p<0.001, p=0.022, and p=0.019 respectively). ROC analysis was performed for cystic, common hepatic, and common bile duct length, respectively. Cut-off values ​​were 30.5 mm, 36.5 mm, and 42.5 mm.

CONCLUSION: Extrahepatic bile duct variations are of critical importance in ACC surgery. In the data, as the cystic duct and common bile duct lengthens, the possibility of ACC increases. There is need for studies with larger samples.

KEY WORDS: Acute calculous cholecystitis, Extrahepatic biliary tract, Anatomical variations, Cholelithiasis.

PMID:35932121 | DOI:10.29271/jcpsp.2022.08.991

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Nevin Manimala Statistics

Pleth Variability Index Guided Volume Optimisation in Major Gynaecologic Surgery

J Coll Physicians Surg Pak. 2022 Aug;32(8):980-986. doi: 10.29271/jcpsp.2022.08.980.

ABSTRACT

OBJECTIVE: To compare conventional fluid management (CFM) with pleth variability index (PVI) guided goal-directed fluid management (GDFM) during elective total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH+BSO) operations.

STUDY DESIGN: Randomised controlled trial.

PLACE AND DURATION OF STUDY: Department of Anaesthesiology and Reanimation, Faculty of Medicine, Health Sciences University, Kartal Dr. Lutfi Kirdar City Hospital, Istanbul, Turkey, from February to July 2021.

METHODOLOGY: This trial included 78 patients aged 18-65 years with ASA I-III who would undergo elective TAH-BSO under general anaesthesia. Following randomisation with the closed envelope method, standard monitoring, and 250 ml crystalloid infusion during anaesthesia induction, maintenance fluid therapy was administered at 8-10 ml/Kg/hour to the control group and 2-3 ml/Kg/hour to the PVI group. If the mean arterial pressure (MAP) was ≤65 mmHg and/or the MAP was decreased by more than 20%, and the PVI was >13%, a 250 ml colloid bolus was given. When there was no response, a vasoactive agent was administered. Vital signs, laboratory findings, and postoperative complications were evaluated.

RESULTS: Age, weight, BMI, urine output, bleeding, hospital stay, comorbidities, intraoperative use of blood products, and complication rates were not significantly different between the PVI and CFM groups (p>0.05). The PVI group had shorter operational times and used less crystalloid than the control group (p=0.033 and p<0.001, respectively). The PVI group’s postoperative base excess (BE) levels changed significantly less than the control group’s (p<0.001). In both pre- and postoperative haemoglobin, haematocrit, urea, creatinine, electrolytes, and lactate measurements, there were no statistically significant differences between the groups (p>0.05).

CONCLUSION: PVI-GDFM is equally safe as CFM for intraoperative fluid management during elective complete abdominal hysterectomy and bilateral salpingo-oophorectomy procedures.

KEY WORDS: Pleth variability index, Fluid management, Base excess.

PMID:35932119 | DOI:10.29271/jcpsp.2022.08.980

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Nevin Manimala Statistics

Coronary Endarterectomy: Postoperative Angiographic Results

J Coll Physicians Surg Pak. 2022 Aug;32(8):969-974. doi: 10.29271/jcpsp.2022.08.969.

ABSTRACT

OBJECTIVE: To compare the postoperative graft patency rates of patients who had undergone coronary endarterectomies (CE) during coronary bypass surgery to those of patients who had not had CE, based on postoperative coronary angiography.

STUDY DESIGN: Comparative descriptive study.

PLACE AND DURATION OF STUDY: Coronary Angiography Unit, Tınaztepe University Faculty of Medicine, Turkey, from November 2010 through June 2021.

METHODOLOGY: Patients who had undergone CE during coronary bypass surgery were included. Postoperative morbidity results and the patency rates of the vessels with and without endarterectomy were evaluated via coronary angiographies that had been performed.

RESULTS: The patency rate in vessels that underwent coronary endarterectomy was determined to be 73.4% according to coronary angiographies performed after an average of 47.7 months. The patency rate in vessels without endarterectomy was 63.7%. The highest patency rate was found in the left anterior descending artery (LAD) in both CE and conventional bypass coronary arteries and the lowest patency rate was found in the diagonal artery (D) in both CE and conventional bypass coronary arteries. In the comparison of vessels with and without CE, the patency rate was found to be 66.6% in patients with CE on the right coronary artery (RCA) and 45.7% in patients without CE on the right coronary artery and the difference was statistically significant (p<0.037).

CONCLUSION: Coronary endarterectomy should be used when it is believed that a simple anastomosis would not provide adequate patency during coronary bypass surgery because the primary goal should be to achieve full revascularization and a long-term patency rate.

KEY WORDS: Coronary angiography, Coronary bypass grafting, Endarterectomy, Patency rate.

PMID:35932117 | DOI:10.29271/jcpsp.2022.08.969

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Nevin Manimala Statistics

Assessment of Neurological Impairment and Recovery Using Statistical Models of Neurologically Healthy Behavior

Neurorehabil Neural Repair. 2022 Aug 5:15459683221115413. doi: 10.1177/15459683221115413. Online ahead of print.

ABSTRACT

While many areas of medicine have benefited from the development of objective assessment tools and biomarkers, there have been comparatively few improvements in techniques used to assess brain function and dysfunction. Brain functions such as perception, cognition, and motor control are commonly measured using criteria-based, ordinal scales which can be coarse, have floor/ceiling effects, and often lack the precision to detect change. There is growing recognition that kinematic and kinetic-based measures are needed to quantify impairments following neurological injury such as stroke, in particular for clinical research and clinical trials. This paper will first consider the challenges with using criteria-based ordinal scales to quantify impairment and recovery. We then describe how kinematic-based measures can overcome many of these challenges and highlight a statistical approach to quantify kinematic measures of behavior based on performance of neurologically healthy individuals. We illustrate this approach with a visually-guided reaching task to highlight measures of impairment for individuals following stroke. Finally, there has been considerable controversy about the calculation of motor recovery following stroke. Here, we highlight how our statistical-based approach can provide an effective estimate of impairment and recovery.

PMID:35932111 | DOI:10.1177/15459683221115413

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Nevin Manimala Statistics

Evaluating the Impact of an Educational Intervention on Hepatitis C Screening in a Midwest Regional Psychiatric Unit

J Am Psychiatr Nurses Assoc. 2022 Aug 5:10783903221115741. doi: 10.1177/10783903221115741. Online ahead of print.

ABSTRACT

INTRODUCTION: Affecting more than 3.9 million Americans, the hepatitis C virus (HCV) attacks the liver by causing inflammation. Left untreated, HCV can lead to serious consequences. Targeting high-risk individuals in the inpatient psychiatric setting can lead to increased testing and referral.

AIMS: This quality improvement project determined whether an intervention-consisting of a pretest, educational session, posttest, and screening implementation-increased staff knowledge about HCV screening recommendations, identified at-risk individuals, and increased the number of patients screened and referred for treatment.

METHOD: An online HCV educational session was provided to 30 staff at a Midwest regional psychiatric unit. An online pre/posttest was conducted to determine staff knowledge and understanding prior to and after the educational session. An HCV screening tool checklist was incorporated into the electronic health record (EHR) system. A 3-month pre/post-intervention chart review was completed to determine the number of patients identified and screened for HCV.

RESULTS: A comparison of the 30 staff members’ mean pre/posttest scores were calculated using an unpaired t test, showing a prescore mean of 55.15 ± 19.09 and a postscore mean of 85.75 ± 13.44, p < .001. A chi-square analysis indicated that there was a statistically significant post-intervention increase in the percentage of high-risk patients identified (5.6%-36.4%, p < .001) and screened (5.6%-31.4%, p < .001) for HCV compared with pre-intervention.

CONCLUSION: The study intervention increased staff knowledge of HCV guidelines and the number of at-risk patients identified and screened for the disease.

PMID:35932102 | DOI:10.1177/10783903221115741