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Nevin Manimala Statistics

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.

ABSTRACT

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.

ABSTRACT

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

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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.

ABSTRACT

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.

ABSTRACT

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

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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.

ABSTRACT

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

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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.

ABSTRACT

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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Nevin Manimala Statistics

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.

ABSTRACT

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

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Nevin Manimala Statistics

Assessment of domestic violence and its associated factors among ever-married reproductive-age women in Cameroon: a cross-sectional survey

BMC Womens Health. 2022 Oct 1;22(1):397. doi: 10.1186/s12905-022-01907-7.

ABSTRACT

BACKGROUND: Domestic violence (DV) against women is a global issue that affects women in all countries and is a significant contributor to their poor health. Women who have experienced DV, in particular, suffer from the gynecological, nervous system, and stress-related issues. Despite such devastating implications, there is a paucity of data on the prevalence of DV and its associated factors among married reproductive-age women in Cameroon.

METHOD: The data were analyzed by using STATA version 14 from a demographic and health survey conducted in Cameroon in 2018. Both bivariable and multivariable logistic regression analyses were done. Statistical significance was determined using a p-value of less than 0.05 and a 95% confidence range.

RESULT: A total of 4,903 ever-married women were included in the study. The mean age ± standard deviation, of the participants was 31.3 (± 8.4) years with an age range of 15-49 years. The prevalence of DV among ever-married Cameroonian women was 30.5% with 95%CI (29.3%, 31.8%). Women’s educational attainment (higher educational level) (AOR = 0.58, 95% CI (0.37, 0.92), p value = 0.02), Husband’s educational level (husbands who attended primary educational level (AOR = 1.30, 95% CI (1.01, 1.68), p value = 0.04), a woman who had media exposure regarding DV ( AOR = 0.83, 95% CI (0.0, 0.99), p value = 0.04), a woman whose husband drinks alcohol (AOR = 3.00, 95% CI (2.56, 3.53), p value < 0.001), and the region where the women reside (center without Yaoundé (AOR = 2.48, 95% CI (1.75, 3.52), p value < 0.001), west (AOR = 1.49, 95% CI (1.05, 2.11), p value = 0.02), South (AOR = 1.89, 95% CI (1.31, 2.72), p-value = 0.001), and Yaoundé (AOR = 1.65. 95% CI (1.14, 2.39), p value = 0.009) were factors that were significantly associated to DV committed by a husband in the previous 12 months against ever-married women.

CONCLUSION: The present study revealed that the prevalence of DV among ever-married women in Cameroon is high. Women’s educational level, husband’s educational level, husband’s alcohol drinking status, women’s exposure to mass-media about DV, and the region where the woman resides in the country were factors significantly associated with DV.

PMID:36183059 | DOI:10.1186/s12905-022-01907-7

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Nevin Manimala Statistics

The spatio-temporal dynamics of infant mortality in Ecuador from 2010 to 2019

BMC Public Health. 2022 Oct 1;22(1):1841. doi: 10.1186/s12889-022-14242-1.

ABSTRACT

The infant mortality rate (IMR) is still a key indicator in a middle-income country such as Ecuador where a slightly increase up to 11.75 deaths per thousand life births has been observed in 2019. The purpose of this study is to propose and apply a prioritization method that combines clusters detection (Local Indicators of Spatial Association, LISA) and a monotonic statistic depicting time trend over 10 years (Mann-Kendall) at municipal level. Annual national databases (2010 to 2019) of live births and general deaths are downloaded from National Institute of Statistics and Censuses (INEC). The results allow identifying a slight increase in the IMR at the national level from 9.85‰ in 2014 to 11.75‰ in 2019, neonatal mortality accounted for 60% of the IMR in the last year. The LISA analysis allowed observing that the high-high clusters are mainly concentrated in the central highlands. At the local level, Piñas, Cuenca, Ibarra and Babahoyo registered the highest growth trends (0.7,1). The combination of techniques made it possible to identify eight priority counties, half of them pertaining to the highlands region, two to the coastal region and two to the Amazon region. To keep infant mortality at a low level is necessary to prioritize critical areas where public allocation of funds should be concentrated and formulation of policies.

PMID:36183054 | DOI:10.1186/s12889-022-14242-1

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Efficacy of subtenon 20-mg triamcinolone injection versus 0.1% dexamethasone eye drops for controlling inflammation after phacoemulsification: a randomized controlled trial

Sci Rep. 2022 Oct 1;12(1):16471. doi: 10.1038/s41598-022-20522-y.

ABSTRACT

A prospective randomized control trial of 140 eyes from 140 patients, who underwent phacoemulsification, was conducted to compare the efficacy of subtenon corticosteroids injection with corticosteroids eye drops for controlling postoperative intraocular inflammation. Seventy patients received subtenon 20-mg triamcinolone injection (TA group), whereas the other 70 patients received 0.1% dexamethasone eye drops (Dexa group) after the uneventful surgeries. We examined and measured anterior chamber inflammation (ACI) score, laser flare-cell metering, conjunctival redness, pain, discomfort, visual acuity, intraocular pressure, and central foveal thickness on 1, 7, 14, 28 and 90 days postoperatively. At one month after the surgery, full recovery (zero ACI score) was found in 43 patients (63.20%) in the Dexa group versus 47 patients (68.10%) in the TA group (p = 0.55). There were no statistically significant differences in aqueous cells (p = 0.37) and flare (p = 0.86) between the two groups at one month. All participants experienced no serious adverse events. In conclusion, we found no statistically significant difference between subtenon 20-mg triamcinolone injection and 0.1% dexamethasone eye drop to control inflammation postoperatively. A single subtenon 20-mg triamcinolone injection could be an alternative anti-inflammatory treatment for an uneventful phacoemulsification.

PMID:36183042 | DOI:10.1038/s41598-022-20522-y