Nevin Manimala Statistics

Ablative Fractional Carbon Dioxide Laser Combined with Autologous Platelet-Rich Plasma in the Treatment of Atrophic Acne Scars: A Systematic Review and Meta-Analysis

Dermatol Ther. 2022 Oct 1:e15888. doi: 10.1111/dth.15888. Online ahead of print.


BACKGROUND: Atrophic acne scars are the most common cutaneous seqaule of acne vulgaris, representing 80-90% of all acne scars. Ablative fractional carbon dioxide (FCO2) laser is the gold standard treatment for atrophic scars. Additionally, platelet-rich plasma (PRP) is suggested to accelerate the healing process and collagen synthesis. The aim of the present systematic review and meta-analysis was to determine the efficacy and safety of PRP combined with Ablative FCO2 laser in the treatment of moderate to severe atrophic acne scars.

METHODS: Randomized controlled trials (RCTs) that have compared PRP in combination with ablative FCO2 laser to ablative FCO2 laser alone with respect to the efficacy and safety measures were included. We have systematically explored Embase, Medline, and CENTRAL databases via Ovid. The outcomes that our systematic review saught to evaluate were clinical improvement, patient satisfaction, and Goodman and Baron’s qualitative acne scar score. The dichotomous outcomes were presented as odds ratio (OR) while the continuous outcomes were presented as standardized mean difference (SMD).

RESULTS: 11 RCTs that represents 313 participants were included. The combined use of laser and PRP showed a statistically significant clinical improvement and patient satisfaction compared to the use of laser alone (OR=2.56, 95% CI 1.37 to 4.78 and OR=3.38, 95% CI 1.80 to 6.34, respectively). Also, a significant improvement in Goodman and Baron’s score was achieved by combining PRP with laser (SMD = -0.40, 95% CI -0.65 to -0.14).

CONCLUSION: The combined treatment of laser and PRP was highly synergistic, effective, and safe in treating moderate to severe atrophic acne scars. This article is protected by copyright. All rights reserved.

PMID:36183145 | DOI:10.1111/dth.15888

Nevin Manimala Statistics

Working with alcohol prevention in occupational health services: “knowing how” is more important than “knowing that” – the WIRUS OHS study

Addict Sci Clin Pract. 2022 Oct 1;17(1):54. doi: 10.1186/s13722-022-00335-0.


BACKGROUND: Alcohol consumption is a major public health challenge; the majority of employees consume alcohol regularly and a considerable proportion of employees can be characterized as risky drinkers in need of interventions. Occupational health services (OHS) are uniquely positioned for implementing alcohol prevention interventions targeting employees, but rarely do so. Studies have shown that lack of knowledge among OHS personnel is a barrier to alcohol prevention activity. This study aimed to explore OHS personnels’ levels of theoretical and practical alcohol knowledge, and whether these two ways of knowing were differentially associated with alcohol prevention activity.

METHODS: In this cross-sectional study, survey data were collected from 322 OHS personnel in Norway in 2018 (response rate = 53.6%). The survey included variables of two ways of knowing (theoretical and practical) and three types of doing (intervention frequency, conducting individual interventions, and conducting group interventions). Data were analyzed with descriptive statistics, paired sample t-tests, bivariate correlations, and adjusted linear and logistic regression analyses.

RESULTS: OHS personnel rated their theoretical alcohol knowledge higher than their practical knowledge (η2 = 0.33, p < 0.001). Higher reported levels of practical knowledge were associated with higher intervention frequency (b = 0.39, β = 0.60, p < 0.001) and greater likelihood of conducting individual interventions (OR = 1.60, p < .001) as well as group interventions (OR = 1.84, p < 0.001). Theoretical knowledge was not associated with conducting interventions, and there was no evidence of an interaction between the two ways of knowing in their association with doing. Sensitivity analyses did not indicate clustering effects of OHS personnel being employed within different units.

CONCLUSIONS: Different ways of knowing about alcohol among OHS personnel were dissimilarly associated with conducting alcohol prevention interventions in occupational health settings. For doing, knowing how seems to be more important than knowing that. Training programs for OHS personnel should emphasize knowledge about how to deal with alcohol-related issues and how to conduct prevention interventions, rather than focus on detrimental effects of alcohol.

PMID:36183127 | DOI:10.1186/s13722-022-00335-0

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Large inferior retinectomies for proliferative vitreoretinopathy in silicone oil-filled eyes

Int J Retina Vitreous. 2022 Oct 1;8(1):73. doi: 10.1186/s40942-022-00420-1.


BACKGROUND: To describe the anatomical and functional outcomes and late complications in patients who developed inferior proliferative vitreoretinopathy (PVR) in silicone oil-filled eyes and who required reoperation with large inferior retinectomy.

METHODS: This is a single-center, retrospective, interventional case series analysis. The study involved 18 individuals with tractional retinal re-detachment due to PVR development inferiorly in eyes who had undergone prior pars plana vitrectomy and silicone oil as a tamponade. All patients included in the study underwent secondary surgery with large inferior retinectomy (from 120° to 270°) and silicone oil filling.

RESULTS: The mean follow-up period was 44.0 ± 31.5 (± SD) months (range: 4 to 96 months. The anatomical success, defined as the complete reattachment of the retina until the last follow-up, was observed in 88.9% of the cases. The postoperative visual acuity ranged from 20/100 to hand motion at 60 cm. Only two cases (11.1%) did not achieve anatomical success at the last follow-up due to recurrent PVR and retinal re-detachment (one including hypotony). All of the patients were pseudophakic. The PVR grade, as well as the presence of PVR prior to primary surgery, showed no statistical correlation with BCVA, the extent of retinectomies, and final macular status. There was a statistically significant correlation between “Final BCVA” and “Initial BCVA” (r = 0.654) and between “Final BCVA” and “Extent of Retinectomy” (r = 0.615).

CONCLUSIONS: Reoperation in eyes filled with silicone oil may be required when PVR is developed. Secondary surgery in these cases with large inferior retinectomy and silicone oil implantation may reach good anatomical success with low rates of late complications, besides improving visual acuity. A better BCVA at the time of re-RD diagnosis and cases of retinectomies with greater extensions showed a positive correlation with better functional outcomes. Trial registration Research Ethics Committee of the Suel Abujamra Institute reviewed and approved this study protocol (approval number, 5.404.961).

PMID:36183118 | DOI:10.1186/s40942-022-00420-1

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Does functional planning, 3D templating and patient-specific instrumentation improve accuracy in total hip replacement?- a randomized controlled trial

Arthroplasty. 2022 Oct 2;4(1):43. doi: 10.1186/s42836-022-00143-6.


AIMS: Debate continues as to the optimal orientation of the acetabular component in total hip arthroplasty (THA) and how to reliably achieve this. The primary objective of this study was to compare functional CT-based planning and patient-specific instruments with conventional THA using 2D templating.

METHODS: A pragmatic single-center, patient-assessor blinded, randomized control trial of patients undergoing THA was performed. 54 patients (aged 18-70) were recruited to either Corin Optimized Positioning System (OPS) or conventional THA. All patients received a cementless acetabular component. All patients underwent pre- and postoperative CT scans, and four functional X-rays. Patients in the OPS group had a 3D surgical plan and bespoke guides made. Patients in the conventional group had a surgical plan based on 2D templating X-rays. The primary outcome measure was the mean error in acetabular anteversion as determined by postoperative CT scan.

RESULTS: There was no statistically significant difference in the mean error in angle of acetabular anteversion when comparing OPS and conventional THA. In the OPS group, the achieved acetabular anteversion was within 10° of the planned anteversion in 96% of cases, compared with only 76% in the conventional group. The clinical outcomes were comparable between the groups.

CONCLUSION: Large errors in acetabular orientation appear to be reduced when CT-based planning and patient-specific instruments are used compared to the standard technique but no significant differences were seen in the mean error.

PMID:36183111 | DOI:10.1186/s42836-022-00143-6

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Efficacy of native cyclopoid copepods in biological vector control with regard to their predatory behavior against the Asian tiger mosquito, Aedes albopictus

Parasit Vectors. 2022 Oct 1;15(1):351. doi: 10.1186/s13071-022-05460-y.


BACKGROUND: The control of the Asian tiger mosquito Aedes albopictus (Diptera: Culicidae) is crucial owing to its high vector competence for more than 20 arboviruses-the most important being dengue, chikungunya and Zika virus. Aedes albopictus has an enormous adaptive potential, and its invasive spreading across urban and suburban environments poses challenges for its control. Therefore, all suitable, cost-effective and eco-friendly control tools should be put into practice. In this context, cyclopoid copepods are already known as effective predators of mosquito larvae. This study reports an essential preliminary step towards the integration of copepods into the vector control strategy in Germany, in order to provide a sustainable tool in an integrated control strategy based on the elimination or sanitation of breeding sites, the use of formulations based on Bacillus thuringiensis israelensis (Bti.) and the sterile insect technique (SIT).

METHODS: The predatory potential of native cyclopoid copepods, namely the field-derived species Megacyclops viridis (Crustacea: Cyclopidae), was examined against the larvae of Ae. albopictus, and for comparison, against the larvae of the common house mosquito, Culex pipiens sensu lato (Diptera: Culicidae). The use of different larval instars as prey, and various predator-to-prey ratios, were examined under laboratory and semi-field conditions. The compatibility of Bti. applications along with the use of copepods was assessed in the laboratory.

RESULTS: High predation efficiency of M. viridis upon first-instar larvae of Ae. albopictus was observed under laboratory (up to 96%) and semi-field conditions (65.7%). The copepods did not prey upon stages further developed than the first instars, and in comparison with Ae. albopictus, the predation rates on the larvae of Cx. pipiens s.l. were significantly lower.

CONCLUSIONS: The results indicate a high predation potential of M. viridis against Ae. albopictus larvae, even though strong larval stage and mosquito species preferences were implicated. The integration of copepods as a promising biocontrol agent to the vector control strategy in Germany is therefore highly recommended, especially because of the excellent compatibility of copepods with the use of Bti. However, further research is required, concerning all the probable parameters that may impact the copepod performance under natural conditions.

PMID:36183110 | DOI:10.1186/s13071-022-05460-y

Nevin Manimala Statistics

Stillbirths in Cameroon: an analysis of the 1998-2011 demographic and health surveys

BMC Pregnancy Childbirth. 2022 Oct 1;22(1):736. doi: 10.1186/s12884-022-04993-5.


BACKGROUND: Many countries, including Cameroon, have found it challenging to estimate stillbirths, as there are limited available reports accurately. This analysis aimed to assess stillbirth rates and identify risk factors for stillbirth in Cameroon using successive Demographic and Health Survey data.

METHODS: We conducted a cross-sectional analysis of data collected during the Demographic and Health Surveys of 1998, 2004, and 2011. Data were analyzed using SPSS 20.0. Logistic regressions were used to identify factors associated with stillbirth through odds ratios (ORs) at 95% confidence intervals (CI). Results were considered statistically significant at p-value less than 0.05.

RESULTS: The crude stillbirth rate was 21.4 per 1,000 births in 2004 and 24 per 1,000 births in 2011, with respective standard errors of 1.8 and 1.3. The stillbirth rate increased with the mother’s age (p < 0.001). The stillbirth rate reduction was prolonged between 1998 and 2011, with an annual reduction rate of 1.6%. The study observed that residing in rural areas, low socioeconomic status, and low level of education were risk factors associated with stillbirths.

CONCLUSION: Cameroon’s stillbirth rate remains very high, with a slow reduction rate over the last 20 years. Although some efforts are ongoing, there is still a long way forward to bend the curve for stillbirths in Cameroon; supplementary strategies must be designed and implemented, especially among rural women, the poor, and the less educated.

PMID:36183095 | DOI:10.1186/s12884-022-04993-5

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Required sample size to detect mediation in 3-level implementation studies

Implement Sci. 2022 Oct 1;17(1):66. doi: 10.1186/s13012-022-01235-2.


BACKGROUND: Statistical tests of mediation are important for advancing implementation science; however, little research has examined the sample sizes needed to detect mediation in 3-level designs (e.g., organization, provider, patient) that are common in implementation research. Using a generalizable Monte Carlo simulation method, this paper examines the sample sizes required to detect mediation in 3-level designs under a range of conditions plausible for implementation studies.

METHOD: Statistical power was estimated for 17,496 3-level mediation designs in which the independent variable (X) resided at the highest cluster level (e.g., organization), the mediator (M) resided at the intermediate nested level (e.g., provider), and the outcome (Y) resided at the lowest nested level (e.g., patient). Designs varied by sample size per level, intraclass correlation coefficients of M and Y, effect sizes of the two paths constituting the indirect (mediation) effect (i.e., X→M and M→Y), and size of the direct effect. Power estimates were generated for all designs using two statistical models-conventional linear multilevel modeling of manifest variables (MVM) and multilevel structural equation modeling (MSEM)-for both 1- and 2-sided hypothesis tests.

RESULTS: For 2-sided tests, statistical power to detect mediation was sufficient (≥0.8) in only 463 designs (2.6%) estimated using MVM and 228 designs (1.3%) estimated using MSEM; the minimum number of highest-level units needed to achieve adequate power was 40; the minimum total sample size was 900 observations. For 1-sided tests, 808 designs (4.6%) estimated using MVM and 369 designs (2.1%) estimated using MSEM had adequate power; the minimum number of highest-level units was 20; the minimum total sample was 600. At least one large effect size for either the X→M or M→Y path was necessary to achieve adequate power across all conditions.

CONCLUSIONS: While our analysis has important limitations, results suggest many of the 3-level mediation designs that can realistically be conducted in implementation research lack statistical power to detect mediation of highest-level independent variables unless effect sizes are large and 40 or more highest-level units are enrolled. We suggest strategies to increase statistical power for multilevel mediation designs and innovations to improve the feasibility of mediation tests in implementation research.

PMID:36183090 | DOI:10.1186/s13012-022-01235-2

Nevin Manimala Statistics

Group sequential designs in pragmatic trials: feasibility and assessment of utility using data from a number of recent surgical RCTs

BMC Med Res Methodol. 2022 Oct 1;22(1):256. doi: 10.1186/s12874-022-01734-2.


BACKGROUND: Assessing the long term effects of many surgical interventions tested in pragmatic RCTs may require extended periods of participant follow-up to assess effectiveness and use patient-reported outcomes that require large sample sizes. Consequently the RCTs are often perceived as being expensive and time-consuming, particularly if the results show the test intervention is not effective. Adaptive, and particularly group sequential, designs have great potential to improve the efficiency and cost of testing new and existing surgical interventions. As a means to assess the potential utility of group sequential designs, we re-analyse data from a number of recent high-profile RCTs and assess whether using such a design would have caused the trial to stop early.

METHODS: Many pragmatic RCTs monitor participants at a number of occasions (e.g. at 6, 12 and 24 months after surgery) during follow-up as a means to assess recovery and also to keep participants engaged with the trial process. Conventionally one of the outcomes is selected as the primary (final) outcome, for clinical reasons, with others designated as either early or late outcomes. In such settings, novel group sequential designs that use data from not only the final outcome but also from early outcomes at interim analyses can be used to inform stopping decisions. We describe data from seven recent surgical RCTs (WAT, DRAFFT, WOLLF, FASHION, CSAW, FIXDT, TOPKAT), and outline possible group sequential designs that could plausibly have been proposed at the design stage. We then simulate how these group sequential designs could have proceeded, by using the observed data and dates to replicate how information could have accumulated and decisions been made for each RCT.

RESULTS: The results of the simulated group sequential designs showed that for two of the RCTs it was highly likely that they would have stopped for futility at interim analyses, potentially saving considerable time (15 and 23 months) and costs and avoiding patients being exposed to interventions that were either ineffective or no better than standard care. We discuss the characteristics of RCTs that are important in order to use the methodology we describe, particularly the value of early outcomes and the window of opportunity when early stopping decisions can be made and how it is related to the length of recruitment period and follow-up.

CONCLUSIONS: The results for five of the RCTs tested showed that group sequential designs using early outcome data would have been feasible and likely to provide designs that were at least as efficient, and possibly more efficient, than the original fixed sample size designs. In general, the amount of information provided by the early outcomes was surprisingly large, due to the strength of correlations with the primary outcome. This suggests that the methods described here are likely to provide benefits more generally across the range of surgical trials and more widely in other application areas where trial designs, outcomes and follow-up patterns are structured and behave similarly.

PMID:36183085 | DOI:10.1186/s12874-022-01734-2

Nevin Manimala Statistics

Comparison of response evaluation criteria in solid tumors and tumor regression grade in evaluating the effect of preoperative systemic therapy of gastric cancer

BMC Cancer. 2022 Oct 1;22(1):1031. doi: 10.1186/s12885-022-10125-1.


BACKGROUND: Both Response Evaluation Criteria in Solid Tumors (RECIST) and tumor regression grade (TRG) play key roles in evaluating tumor response. We analyzed the consistency of TRG and RECIST 1.1 for gastric cancer (GC) patients and compared their prognostic values.

METHODS: Patients with GC who received preoperative chemotherapy or chemoimmunotherapy and had records of TRG from December 2013 to October 2021 were enrolled retrospectively. TRG 0-1 and 2-3 are considered as corresponding to complete response (CR)/partial response (PR) and stable disease (SD)/progress disease (PD) in RECIST 1.1, respectively. The primary endpoints were disease-free survival (DFS) and overall survival (OS). The consistency of RECIST and TRG was examined by kappa statistics. Survival analysis was performed using the Kaplan Meier method.

RESULT: One hundred fifty seven GC patients were enrolled, including 125 with preoperative chemotherapy and 32 with chemoimmunotherapy. Among them, 56 patients had measurable lesions. Only 19.6% (11/56) of the patients had consistent results between RECIST 1.1 and TRG. TRG was correlated with both OS and DFS (P = 0.02 and 0.03, respectively) while response according to RECIST1.1 was not (P = 0.86 and 0.23, respectively). The median DFS had not reached in the TRG 0-1 group and was 16.13 months in TRG 2-3 group. TRG 2-3 was associated with young age and peritoneal or liver metastasis. Besides, preoperative chemoimmunotherapy had a significantly higher pCR rate than chemotherapy alone (34.4% vs 8.0%, P < 0.001).

CONCLUSION: TRG was in poor agreement with RECIST 1.1. TRG was better than RECIST 1.1 in predicting DFS and OS for GC patients who received preoperative therapy.

PMID:36183074 | DOI:10.1186/s12885-022-10125-1

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A dose-finding design for phase I clinical trials based on Bayesian stochastic approximation

BMC Med Res Methodol. 2022 Oct 1;22(1):258. doi: 10.1186/s12874-022-01741-3.


BACKGROUND: Current dose-finding designs for phase I clinical trials can correctly select the MTD in a range of 30-80% depending on various conditions based on a sample of 30 subjects. However, there is still an unmet need for efficiency and cost saving.

METHODS: We propose a novel dose-finding design based on Bayesian stochastic approximation. The design features utilization of dose level information through local adaptive modelling and free assumption of toxicity probabilities and hyper-parameters. It allows a flexible target toxicity rate and varying cohort size. And we extend it to accommodate historical information via prior effective sample size. We compare the proposed design to some commonly used methods in terms of accuracy and safety by simulation.

RESULTS: On average, our design can improve the percentage of correct selection to about 60% when the MTD resides at a early or middle position in the search domain and perform comparably to other competitive methods otherwise. A free online software package is provided to facilitate the application, where a simple decision tree for the design can be pre-printed beforehand.

CONCLUSION: The paper proposes a novel dose-finding design for phase I clinical trials. Applying the design to future cancer trials can greatly improve the efficiency, consequently save cost and shorten the development period.

PMID:36183071 | DOI:10.1186/s12874-022-01741-3