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Nevin Manimala Statistics

How large should the next study be? Predictive power and sample size requirements for replication studies

Stat Med. 2022 Apr 8. doi: 10.1002/sim.9406. Online ahead of print.

ABSTRACT

We use information derived from over 40K trials in the Cochrane Collaboration database of systematic reviews (CDSR) to compute the replication probability, or predictive power of an experiment given its observed (two-sided) P$$ P $$ -value. We find that an exact replication of a marginally significant result with P=.05$$ P=.05 $$ has less than 30% chance of again reaching significance. Moreover, the replication of a result with P=.005$$ P=.005 $$ still has only 50% chance of significance. We also compute the probability that the direction (sign) of the estimated effect is correct, which is closely related to the type S error of Gelman and Tuerlinckx. We find that if an estimated effect has P=.05$$ P=.05 $$ , there is a 93% probability that its sign is correct. If P=.005$$ P=.005 $$ , then that probability is 99%. Finally, we compute the required sample size for a replication study to achieve some specified power conditional on the p$$ p $$ -value of the original study. We find that the replication of a result with P=.05$$ P=.05 $$ requires a sample size more than 16 times larger than the original study to achieve 80% power, while P=.005$$ P=.005 $$ requires at least 3.5 times larger sample size. These findings confirm that failure to replicate the statistical significance of a trial does not necessarily indicate that the original result was a fluke.

PMID:35396714 | DOI:10.1002/sim.9406

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Nevin Manimala Statistics

Prevalence and features of delirium in older patients admitted to rehabilitation facilities: a multicenter study

Aging Clin Exp Res. 2022 Apr 8. doi: 10.1007/s40520-022-02099-8. Online ahead of print.

ABSTRACT

BACKGROUND: Delirium is thought to be common across various settings of care; however, still little research has been conducted in rehabilitation.

AIM: We investigated the prevalence of delirium, its features and motor subtypes in older patients admitted to rehabilitation facilities during the three editions of the “Delirium Day project”.

METHODS: We conducted a cross-sectional study in which 1237 older patients (age ≥ 65 years old) admitted to 50 Italian rehabilitation wards during the three editions of the “Delirium Day project” (2015 to 2017) were included. Delirium was evaluated through the 4AT and its motor subtype with the Delirium Motor Subtype Scale.

RESULTS: Delirium was detected in 226 patients (18%), and the most recurrent motor subtype was mixed (37%), followed by hypoactive (26%), hyperactive (21%) and non-motor one (16%). In a multivariate Poisson regression model with robust variance, factors associated with delirium were: disability in basic (PR 1.48, 95%CI: 1.17-1.9, p value 0.001) and instrumental activities of daily living (PR 1.58, 95%CI: 1.08-2.32, p value 0.018), dementia (PR 2.10, 95%CI: 1.62-2.73, p value < 0.0001), typical antipsychotics (PR 1.47, 95%CI: 1.10-1.95, p value 0.008), antidepressants other than selective serotonin reuptake inhibitors (PR 1.3, 95%CI: 1.02-1.66, p value 0.035), and physical restraints (PR 2.37, 95%CI: 1.68-3.36, p value < 0.0001).

CONCLUSION: This multicenter study reports that 2 out 10 patients admitted to rehabilitations had delirium on the index day. Mixed delirium was the most prevalent subtype. Delirium was associated with unmodifiable (dementia, disability) and modifiable (physical restraints, medications) factors. Identification of these factors should prompt specific interventions aimed to prevent or mitigate delirium.

PMID:35396698 | DOI:10.1007/s40520-022-02099-8

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Nevin Manimala Statistics

Operating temperature prediction and comparison for rooftop PV arrays in coastal climates of India

Environ Sci Pollut Res Int. 2022 Apr 9. doi: 10.1007/s11356-022-20068-6. Online ahead of print.

ABSTRACT

This article predicts the operational temperature of a 1-MWp rooftop photovoltaic (PV) system installed on buildings of GITAM University, Andhra Pradesh, India, using various temperature models. In the process of photovoltaic conversion, the operating temperature plays a key role, where the module efficiency and output power of the PV module are linearly dependent on temperature. Various temperature models are presented in the literature with simplified working formulas to find the module temperature involving environment and PV system parameters. This study adopts four models NOCT (normal operating cell temperature), Fiaman, Scandia and arbitrary mounting model (AMM), to assess the power, module temperature of the photovoltaic plant and identify the best model to suit the present study location. Their precision is evaluated on a seasonal day (winter, summer, monsoon and autumn) from the measured data. It is observed that winter, summer, monsoon and autumn days have hourly average module temperatures of 45.4 °C, 48.1 °C, 48.2 °C and 45.3 °C, respectively. Results show the highest average DC voltage of 231.2 kW on a summer day with an hourly module temperature of 48.1 °C recorded. The slightest error values of 3.71% MBE, 5.8% NRMSE, 1.89% TS and 0.03% WMBE are noted with the arbitrary mounting temperature model. This study is helpful to validate that the AMM model is best suited for PV simulation in coastal regions.

PMID:35396686 | DOI:10.1007/s11356-022-20068-6

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Nevin Manimala Statistics

Correction to: Lower low‑density lipoprotein cholesterol levels are associated with an increased risk of hematoma expansion and ensuing mortality in acute ICH patients

Neurol Sci. 2022 Apr 9. doi: 10.1007/s10072-022-06064-1. Online ahead of print.

NO ABSTRACT

PMID:35396638 | DOI:10.1007/s10072-022-06064-1

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Nevin Manimala Statistics

Allele frequencies and minor contributor match statistic convergence using simulated population replicates

Int J Legal Med. 2022 Apr 9. doi: 10.1007/s00414-022-02822-0. Online ahead of print.

ABSTRACT

Probabilistic genotyping permits a comparison of forensic evidence given hypotheses regarding the origin of observed short tandem repeat alleles in a mixed DNA profile. Using the publicly available R package forensim, it has been proposed that mixtures with non-contributors from low genetic diversity populations are more likely to be mistakenly identified as contributors to a mixture than non-contributors from high genetic diversity populations. We hypothesized that these observations are attributed to the unique distribution of alleles in the reference population and may not generalize to other samplings of the same population. We used forensim to simulate 200 US populations (50 each of self-reported African-American, Asian-American, European-American, and Hispanic descent). We compared likelihood ratios for 2400 mixtures to those derived from published data and identified stark differences. A minimum of ten population replicates were required to reduce observed differences relative to published data. Deviations from Hardy-Weinberg equilibrium and allele frequency distributions suggest that simulated populations should be sufficiently evaluated for expectations of population genetic parameters prior to use in DNA mixture modeling experiments. Overall, our findings support the utility of forensim and further describe its suitability to model population genetic parameters but suggest that a single population replicate (directly ascertained or simulated) may be insufficient to make conclusions about a given DNA mixture.

PMID:35396663 | DOI:10.1007/s00414-022-02822-0

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Nevin Manimala Statistics

Perineal wound healing after abdominoperineal resection for rectal cancer: a retrospective cohort study

Int J Colorectal Dis. 2022 Apr 8. doi: 10.1007/s00384-022-04141-7. Online ahead of print.

ABSTRACT

PURPOSE: Delayed perineal wound healing is a common complication after abdominoperineal resection (APR) in rectal cancer. The primary aim of this study was to evaluate the number of patients with delayed wound healing after APR. Secondary aims were to identify risk factors, and describe treatment.

METHODS: Prospectively collected data from the Swedish Colorectal Cancer Registry (SCRCR) was used for retrospective analysis of APR performed at Skåne University Hospital Malmö between 2013 and 2018. Medical charts were retrospectively reviewed. Delayed healing was defined as non-healed perineal wound 30 days postoperatively. Patients undergoing extralevator APR requiring reconstruction were excluded. Statistical analysis was made using SPSS. Risk factors for impaired wound healing were analyzed using a multivariable model.

RESULTS: A total of 162 patients were included, of which 114 underwent standard APR (sAPR) and 48 patients intersphincteric APR (isAPR). In the total population, 69% (111/162) were male, with median age 71 (26-87). The overall healing rate was 52% (85/162); 44% (50/114) in sAPR vs 73% (35/48) in isAPR (P < 0.001). Risk factors for impaired healing after multivariable analysis were BMI > 30 (OR 7.0; CI 95% 1.8-26.2, P = 0.004), reoperation (OR 7.9; CI 95% 1.6-39.8, P = 0.013), neoadjuvant radiotherapy (OR 5.2; CI 95% 1.02-25.1, P = 0.047) and sAPR (OR 2.598; CI 95% 1.05-6.41, P = 0.038). Eight percent (13/162) required an intervention (Clavien-Dindo ≥ 3).

CONCLUSION: Delayed perineal wound healing is a frequent complication after APR but the majority could be treated conservatively. Several risk factors were identified. Further studies aiming at interventions reducing delayed perineal wound healing after APR are warranted.

PMID:35396618 | DOI:10.1007/s00384-022-04141-7

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Nevin Manimala Statistics

Impact of Gabapentin on PACU Length of Stay and Perioperative Intravenous Opioid Use for ERAS Hysterectomy Patients

J Med Syst. 2022 Apr 8;46(5):26. doi: 10.1007/s10916-022-01815-1.

ABSTRACT

We investigated the impact of preoperative gabapentin on perioperative intravenous opioid requirements and post anesthesia care unit length of stay (PACU LOS) for patients undergoing laparoscopic and vaginal hysterectomies within an Enhanced Recovery After Surgery (ERAS) pathway. A multidisciplinary team retrospectively examined 2,015 patients who underwent laparoscopic or vaginal hysterectomies between October 2016 and January 2020 at a single academic institution. The average PACU LOS was 168 min among patients who did not receive gabapentin vs. 180 min both among patients who received ≤ 300 mg of gabapentin and patients who received > 300 mg of gabapentin. After adjusting for demographics and medical comorbidities, PACU LOS for patients given ≤ 300 mg gabapentin was 6% longer (rate ratio (RR) = 1.06, 95% CI = 1.01-1.11) than for patients who were not given gabapentin, and for patients who received > 300 mg of gabapentin was 7% longer (RR = 1.07, 95%CI = 1.01-1.13) than for those who did not receive gabapentin. Patients who received ≤ 300 mg gabapentin received 9% less perioperative intravenous hydromorphone than patients who did not receive gabapentin (RR = 0.91, 95% CI = 0.86 – 0.97); patients who received > 300 mg of gabapentin received 12% less perioperative intravenous hydromorphone than patients who did not receive gabapentin (RR = 0.88, 95% CI = 0.82 – 0.95). These findings represent an absolute difference of 0.09 mg intravenous hydromorphone. There were no statistically significant differences in total intravenous fentanyl received. Preoperative gabapentin given as part of an ERAS pathway is associated with statistically but not clinically significant increases in PACU LOS and decreases in total perioperative intravenous opioid use.

PMID:35396607 | DOI:10.1007/s10916-022-01815-1

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Nevin Manimala Statistics

Real-world experience of anti-D immunoglobulin in immune thrombocytopenia

Ann Hematol. 2022 Apr 8. doi: 10.1007/s00277-022-04829-4. Online ahead of print.

ABSTRACT

In developing countries, anti-D has been used in immune thrombocytopenia (ITP) as a cheaper alternative to human immunoglobulin. We aim to analyze the response and safety profile of anti-D in patients with severe ITP. A retrospective study was conducted at a tertiary care hospital in Northern India. Patients received a single intravenous infusion of 75 μg/kg anti-D. In total, 36 patients (20 females) were included in this study. The median duration from ITP diagnosis to anti-D therapy was 235 days (range 1-1613 days). Four (11.1%) patients received anti-D as an upfront treatment. The patients’ platelet counts rose significantly by the end of day three and continued to be significantly high until day 30 of receiving anti-D (p ≤ 0.001). The overall response rate (ORR) by day seven was 88.89%. There was no effect of age, sex, duration of disease, prior therapy, and platelet count on the ORR. Patients were followed up for a median duration of 52 days (longest follow-up: 3080 days). Six (6/36, 16.67%) patients continued to be in remission till the last follow-up. The hemoglobin fall was statistically significant on day three and day seven (p < 0.001 and p = 0.001) and got normalized by day 30. We observed equally good ORR in mixed populations and different phases of ITP along with long-term sustained response. The study demonstrates a quick and high response rate along with good safety profile to anti-D in all forms of ITP.

PMID:35396605 | DOI:10.1007/s00277-022-04829-4

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Nevin Manimala Statistics

Fixation of platelet-rich plasma and fibrin gels on knee cartilage defects after microfracture with arthroscopy

Int Orthop. 2022 Apr 8. doi: 10.1007/s00264-022-05377-2. Online ahead of print.

ABSTRACT

PURPOSE: An investigation of arthroscopic surgery combined with coverage of the microfractured wound surface with platelet-rich plasma (PRP) and fibrin gels (FG) to treat knee cartilage defects.

METHODS: Between February 2017 and February 2020, 145 patients with knee cartilage defects were treated. Only isolated full-thickness cartilage defects were included, and 28 patients (12 men and 16 women) were included in this study. They were all treated with arthroscopic surgery on subchondral bones, filled with PRP and thrombin, and sealed with FG. The knee pain visual analogue scale (VAS) scores were measured after the patients climbed ten stairs up and down, and the Western Ontario and McMaster Universities osteoarthritis index and the area of cartilage defects were measured through the pre-operative and post-operative follow-up. The complication incidences were also observed.

RESULTS: All patients were followed up for ten to 15 months (median 12 months). The knee pain VAS scores decreased from 6.57 ± 1.07 pre-operatively to 2.09 ± 1.35 at the last follow-up. The WOMAC osteoarthritis index decreased from 44.32 ± 3.95 (mean ± sd) pre-operatively to 16.57 ± 2.20 by the last follow-up. The cartilage defect decreased from 2.93 ± 0.65 cm2 pre-operatively to 1.09 ± 0.69 cm2 at the last follow-up. All scores showed statistically significant improvements after surgery (p < 0.05). No complications were observed.

CONCLUSION: The combination therapy of arthroscopic surgery and covering the microfractured wound surface with PRP and FG can repair knee cartilage defects, relieve pain, and improve function, and is a safe and effective treatment.

PMID:35396606 | DOI:10.1007/s00264-022-05377-2

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Nevin Manimala Statistics

Avoidance of routine endotracheal intubation and general anesthesia for primary closure of gastroschisis: a systematic review and meta-analysis

Pediatr Surg Int. 2022 Apr 8. doi: 10.1007/s00383-022-05117-y. Online ahead of print.

ABSTRACT

PURPOSE: Over the last few decades, several articles have examined the feasibility of attempting primary reduction and closure of gastroschisis without general anesthesia (GA). We aimed to systematically evaluate the impact of forgoing routine intubation and GA during primary bedside reduction and closure of gastroschisis.

METHODS: The primary outcome was closure success. Secondary outcomes were mortality, time to enteral feeding, and length of hospital stay.

RESULTS: 12 studies were included: 5 comparative studies totalling 192 patients and 7 descriptive case studies totalling 56 patients. Primary closure success was statistically equivalent between the two groups, but trended toward improved success with GA/intubation (RR = 0.86, CI 0.70-1.03, p = 0.08). Mortality was equivalent between groups (RR = 1.26, CI 0.26-6.08, p = 0.65). With respect to time to enteral feeds and length of hospital stay, outcomes were either equivalent between the two groups or favored the group that underwent primary closure without intubation and GA.

CONCLUSION: There are few comparative studies examining the impact of performing primary bedside closure of gastroschisis without GA. A meta-analysis of the available data found no statistically significant difference when forgoing intubation and GA. Foregoing GA also did not negatively impact time to enteral feeds, length of hospital stay, or mortality.

PMID:35396604 | DOI:10.1007/s00383-022-05117-y