Tag: statistics

PLoS One. 2021 Sep 15;16(9):e0257005. doi: 10.1371/journal.pone.0257005. eCollection 2021.

ABSTRACT

BACKGROUND: Machine learning (ML) algorithms are now increasingly used in infectious disease epidemiology. Epidemiologists should understand how ML algorithms behave within the context of outbreak data where missingness of data is almost ubiquitous.

METHODS: Using simulated data, we use a ML algorithmic framework to evaluate data imputation performance and the resulting case fatality ratio (CFR) estimates, focusing on the scale and type of data missingness (i.e., missing completely at random-MCAR, missing at random-MAR, or missing not at random-MNAR).

RESULTS: Across ML methods, dataset sizes and proportions of training data used, the area under the receiver operating characteristic curve decreased by 7% (median, range: 1%-16%) when missingness was increased from 10% to 40%. Overall reduction in CFR bias for MAR across methods, proportion of missingness, outbreak size and proportion of training data was 0.5% (median, range: 0%-11%).

CONCLUSION: ML methods could reduce bias and increase the precision in CFR estimates at low levels of missingness. However, no method is robust to high percentages of missingness. Thus, a datacentric approach is recommended in outbreak settings-patient survival outcome data should be prioritised for collection and random-sample follow-ups should be implemented to ascertain missing outcomes.

PMID:34525098 | DOI:10.1371/journal.pone.0257005

Opt Lett. 2021 Sep 15;46(18):4514-4517. doi: 10.1364/OL.436320.

ABSTRACT

Direct epitaxy of InP quantum dot (QD) lasers on silicon (Si) provides an on-chip red laser source for integrated Si photonics with different applications. Here, we demonstrate the first, to the best of our knowledge, InP QD lasers directly grown on (001) Si. Combining highly emissive InP QDs and a GaAs/Si template with low defect density, continuous-wave (CW) lasing of micro-disk lasers (MDLs) on Si is achieved at room temperature. The lowest threshold of MDLs on Si is ∼500nW, without considering the micro-disk surface absorption efficiency of the pump power. The MDLs grown on the native GaAs substrate with the same growth and fabrication process are compared using statistical data analysis. Similar material characterization results and device performances on these two substrates further confirm the performance of QD lasers on Si. This demonstration paves the way for future realization of integrated photonic circuits with red and near-infrared (NIR) lasers on Si.

PMID:34525035 | DOI:10.1364/OL.436320

PLoS Negl Trop Dis. 2021 Sep 15;15(9):e0009781. doi: 10.1371/journal.pntd.0009781. Online ahead of print.

ABSTRACT

BACKGROUND: Ethiopia is one of the scarce rare African countries where Plasmodium vivax and P. falciparum co-exist. There has been no attempt to derive a robust prevalence estimate of P. vivax in the country although a clear understanding of the epidemiology of this parasite is essential for informed decisions. This systematic review and meta-analysis, therefore, is aimed to synthesize the available evidences on the distribution of P. vivax infection by different locations/regions, study years, eco-epidemiological zones, and study settings in Ethiopia.

METHODS: This study was conducted in accordance with Preferred Reposting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Studies conducted and published over the last two decades (2000 to 2020) that reported an estimate of P. vivax prevalence in Ethiopia were included. The Cochrane Q (χ2) and the I2 tests were used to assess heterogeneity, and the funnel plot and Egger’s test were used to examine publication bias. A p-value of the χ2 test <0.05 and an I2 value >75% were considered presence of considerable heterogeneity. Random effect models were used to obtain pooled estimate of P. vivax infection prevalence. This study is registered with PROSPERO (International Prospective Register of Systematic Reviews): ID CRD42020201761.

RESULTS: We screened 4,932 records and included 79 studies that enrolled 1,676,659 confirmed malaria cases, from which 548,214 (32.69%) were P. vivax infections and 1,116,581 (66.59%) were due to P. falciparum. The rest (11,864 or 0.7%) were due to mixed infections. The pooled estimate of P. vivax prevalence rate was 8.93% (95% CI: 7.98-9.88%) with significant heterogeneity (I2 = 100%, p<0.0001). Regional differences showed significant effects (p<0.0001, and I2 = 99.4%) on the pooled prevalence of P. vivax, while study years (before and after the scaling up of interventional activities) did not show significant differences (p = 0.9, I2 = 0%). Eco-epidemiological zones considered in the analysis did show a significant statistical effect (p<0.001, I2 = 78.5%) on the overall pooled estimate prevalence. Also, the study setting showed significant differences (p = 0.001, and I2 = 90.3%) on the overall prevalence, where significant reduction of P. vivax prevalence (4.67%, 95%CI: 1.41-7.93%, p<0.0001) was observed in studies conducted at the community level. The studies included in the review demonstrated lack of publication bias qualitatively (symmetrical funnel plot) and quantitatively [Egger’s test (coefficient) = -2.97, 95% CI: -15.06-9.13, p = 0.62].

CONCLUSION: The estimated prevalence of P. vivax malaria in Ethiopia was 8.93% with P. vivax prevailing in the central west region of Ethiopia, but steadily extending to the western part of the country. Its distribution across the nation varies according to geographical location, study setting and study years.

PMID:34525091 | DOI:10.1371/journal.pntd.0009781

Eur J Endocrinol. 2021 Sep 1:EJE-21-0635.R1. doi: 10.1530/EJE-21-0635. Online ahead of print.

ABSTRACT

AIMS: To assess whether in women with gestational diabetes mellitus (GDM), postpartum plasma glycated CD59 (pGCD59) levels predict conversion to glucose intolerance diagnosed with an oral glucose tolerance test (OGTT).

METHODS: Blood levels of pGCD59 were measured in a case-control study of 105 women with GDM who underwent a 75g OGTT three months postpartum. The 35 postpartum glucose intolerant cases were individually matched for age, BMI, ethnic origin and parity with 70 women with GDM but normal postpartum OGTT (controls). The GDM cohort (105) was also matched with 105 normal glucose tolerant women during pregnancy. pGCD59 was measured by ELISA in standard peptide units (SPU).

RESULTS: Mean pGCD59 postpartum was significantly higher in cases than in controls (1.5 ± 0.6 SPU vs. 1.0 ±0.6 SPU, p<0.001). The area under the receiving operating characteristic curve (AUC) in cases versus controls was 0.72 (95% CI 0.62-0.83) for postpartum pGCD59 and 0.50 (95% CI 0.36-0.61) for postpartum HbA1c. A 0.5-unit increase in postpartum pGCD59 was associated with an OR of 3.3 (95% CI 1.82-6.16, p<0.001) for glucose intolerance postpartum. A pGCD59 cut-off postpartum of 0.9 SPU had a sensitivity of 85.7% (95% CI 69.7-95.2%), specificity of 47.8% (95% CI 35.6-60.2%), positive predictive value of 45.4% (95% CI 33.1-58.2%) and negative predictive value of 86.8% (95% CI 71.9-95.6%). pGCD59 in pregnancy was a poor predictor for glucose intolerance postpartum [AUC of 0.61 (95% CI 0.50-0.72)].

CONCLUSIONS: pGCD59 might identify women at low risk for glucose intolerance postpartum and could help to avoid an OGTT.

PMID:34524975 | DOI:10.1530/EJE-21-0635

J Clin Rheumatol. 2021 Sep 1;27(6S):S308-S315. doi: 10.1097/RHU.0000000000001651.

ABSTRACT

OBJECTIVE: To evaluate the reliability and validity of the Spanish version of the Medical Outcomes Study Pain Severity Scale (MOS-PSS) in patients with rheumatic diseases.

METHODS: A cross-sectional study was carried out from January 2019 to March 2020 using a nonprobabilistic sampling of consecutive cases. The internal consistency of the scale was evaluated through the Cronbach α coefficient and by the item response theory reliability coefficient. Construct validity was evaluated by factor analysis; relationships between MOS-PSS and visual numeric scale for pain, numeric rating scale for pain, and verbal rating scale for pain; and differences between relevant groups. Item response theory-based methods were used to assess item performance.

RESULTS: A clinical sample of 796 outpatients was recruited. Most patients presented moderate to severe pain. Two subscale solutions showed a good model fit in confirmatory factor analysis. The overall model fit of multidimensional generalized partial credit model showed to be adequate. The most discriminating item was “average pain intensity.” Evidence revealed disordered thresholds in 2 items. Collapsing categories resulted in ordered thresholds for all items and significantly improving the overall model fit. The MOS-PSS and modified MOS-PSS yielded high reliability. Both scales were very strongly correlated with numeric rating scale for pain, visual numeric scale for pain, and verbal rating scale for pain (ρ ≥ 0.85). All hypotheses related to subgroups comparison were fulfilled.

CONCLUSIONS: Overall, the Spanish version of the MOS-PSS showed good reliability and construct validity. Nevertheless, the statistical evidence from this study would suggest the modified MOS-PSS should be the version of choice for measuring pain in Mexican patients with rheumatic diseases.

PMID:34525003 | DOI:10.1097/RHU.0000000000001651

Ocul Immunol Inflamm. 2021 Sep 15:1-6. doi: 10.1080/09273948.2021.1974491. Online ahead of print.

ABSTRACT

PURPOSE: To evaluate the effect of surgical mask use on infection rates for office-based periocular surgeries during the pandemic.

METHODS: An Institutional Review Board-approved retrospective review of medical records identified patients who had an office-based oculofacial plastic surgery procedure during the pandemic between March and December 2020. Statistical analysis was used to compare this group to patients that underwent procedures between March and December 2019, prior to the pandemic when neither surgeon nor patient wore a surgical mask.

RESULTS: The study consisted of 680 patients. Thirty-one different types of procedures were encountered. The incidence of infections in 2020 compared to 2019 was not statistically significant (1.12% (n = 3) versus 1.21% (n = 5), p = 1). All patients with infections were treated with oral antibiotics and improved without long-term complications.

CONCLUSIONS: Periocular surgical site infections are uncommon, and the wearing of surgical masks by patient and surgeon during our office-based oculofacial procedures did not change the incidence of SSIs.

PMID:34524950 | DOI:10.1080/09273948.2021.1974491

Health Rep. 2021 Sep 15;32(9):3-13. doi: 10.25318/82-003-x202100900001-eng.

ABSTRACT

BACKGROUND: As Canadian immigration levels increase, knowledge concerning immigrant health becomes increasingly important for health system policy and planning. This study compares the rate of all-cause hospitalization among immigrants with that of their Canadian-born counterparts.

DATA AND METHODS: Using records from the Discharge Abstract Database (2004/2005 to 2016/2017) and the Ontario Mental Health Reporting System (2006/2007 to 2017/2018) linked to the 2016 Longitudinal Immigration Database, this study compared the age-standardized hospitalization rates (ASHRs) among immigrants with those of the Canadian-born population; the latter were obtained from a linkage based on the 2011 National Household Survey. Comparisons were made at the International Classification of Diseases chapter level by immigrant landing year, admission category and world region of birth. Quebec data were not available.

RESULTS: Overall, ASHRs among immigrants were lower than for the Canadian-born population. Immigrants in the economic class had the lowest ASHR, followed by those in the family class and among refugees. After pregnancy was excluded, leading hospitalization causes were similar for immigrants and the Canadian-born population, where top causes included digestive system and circulatory diseases, injuries, and cancer. In male and female immigrants, the ASHRs were lowest among those from East Asia. By landing year, males arriving earlier had the highest ASHR compared with the most recent arrivals. When pregnancy was excluded and while the differential in ASHRs among females by landing year remained, the magnitude was smaller.

INTERPRETATION: These results corroborate those from previous studies suggesting a healthy immigrant effect, but also reveal heterogeneity in ASHRs within the immigrant population. They provide a baseline for comparison of health status between populations, which enables further monitoring and informs health-system policy and planning.

PMID:34523869 | DOI:10.25318/82-003-x202100900001-eng

Health Rep. 2021 Sep 15;32(9):14-26. doi: 10.25318/82-003-x202100900002-eng.

ABSTRACT

BACKGROUND: A comprehensive evaluation of progress in cancer survival for all cancer types combined has not previously been conducted for Canada. The cancer survival index (CSI) is superior to age standardization in measuring such progress.

DATA AND METHODS: Data are from the population-based Canadian Cancer Registry, record-linked to the Canadian Vital Statistics Death database. CSI estimates for both sexes combined were calculated as the weighted sum of the sex- and cancer-specific age-standardized net survival estimates. Sex-specific CSI estimates were calculated separately using sex-specific cancer type weights.

RESULTS: From the 1992-to-1994 period to the 2015-to-2017 period, the five-year CSI increased 8.6 percentage points to 63.7%. It increased by 8.9 percentage points to 61.8% among males, and by 8.2 percentage points to 65.8% among females. The contribution of a cancer and sex combination to change in the CSI over time is a function of its assigned weight and changes in its age-standardized net survival. Female breast was the most influential cancer and sex combination, contributing 10.1% to the overall increase, followed by prostate (8.2%) and female lung (7.3%). The increase in the index since the 2005-to-2007 period was most impacted by lung cancer among both females (11.1%) and males (9.4%). While prostate cancer survival increased over the entire study period, it has recently decreased, resulting in a counterproductive 8.1% contribution since the 2005-to-2007 period.

INTERPRETATION: Steady progress has been made in overall cancer survival in Canada since the early 1990s. Female breast cancer has contributed the most to this progress overall, but more recently female lung cancer has been the most influential.

PMID:34523870 | DOI:10.25318/82-003-x202100900002-eng

Orthop Surg. 2021 Sep 15. doi: 10.1111/os.13025. Online ahead of print.

ABSTRACT

OBJECTIVE: The aim of this study was to compare the radiological features of intravertebral clefts (IVC) between Kümmell disease (KD) and acute osteoporotic vertebral compression fracture (OVCF).

MATERIALS AND METHODS: This is a retrospective study. A total of 79 patients with IVC from January 2014 to December 2018 were included in this study. There were 22 men and 57 women, with an average of 73.5 years. Based on the exact time interval from injury to treatment and the pathological examination results, the patients were divided into KD group (44 patients) and acute OVCF group (35 patients). The two groups were compared by the margin sclerosis of IVC, vertebra and pedicle ossification, stress fracture of the spinous process, paravertebral callus, the shape of IVC, cleft in the adjacent disc, and flatness of IVC’s margin from plain radiographs and computed tomography (CT). The two groups were compared by the IVC content, double-line sign, and signal of fracture vertebral from their magnetic resonance imaging (MRI).

RESULTS: There were no significant differences in sex, age, and fracture distribution between the KD group and the acute OVCF group. IVC was present in both the KD group and the acute OVCF group. Six radiological features were only present in the KD group, including sclerosis of the cleft margin (95.5%, 42/44), ossification of the fractured vertebrae (100%, 44/44), ossification of the pedicle (31.8%, 14/44), double-line sign (27.3%, 12/44), stress fracture of the spinous process (13.6%, 6/44), and even formation of paravertebral callus (18.2%, 8/44). Although there were statistical differences in the other four radiological features of content of IVC (P = 0.02), cleft sign in adjacent intervertebral disc (P < 0.01), margin of IVC (P = 0.02), and the shape of IVC (P = 0.01) between the KD group and acute OVCF group, these characteristics could be found in both groups.

CONCLUSION: IVC could present in patients with both KD and acute OVCF; however, we found that marginal cleft sclerosis, vertebral and pedicle ossification, double-line sign, spinous process fracture, and formation of paravertebral callus are unique radiological features of KD and could be used for differentiation of KD from acute OVCF with IVC.

PMID:34523812 | DOI:10.1111/os.13025

Int J Health Policy Manag. 2021 Sep 1. doi: 10.34172/ijhpm.2021.103. Online ahead of print.

ABSTRACT

BACKGROUND: To assess whether the imposition of the coronavirus disease 2019 (COVID-19) national quarantine (March 10, 2020) resulted in a shift in the proportion of patients operated for hip fracture on the day of admission, the following day and two days after admission in the region of Piedmont, northern Italy.

METHODS: Interrupted time-series analysis (ITSA) comparing hospitalization rate and timing of hip-fracture surgeries between pre- and post-quarantine period. The same data observed in Piedmont the year before were included as a control time series with no “intervention” (quarantine) in the middle of the observation period.

RESULTS: We found that 70.3% and 69.4% of hip-fracture patients received surgery within 2 days of hospital admission in the 16 weeks before and after the national quarantine, respectively. One-day surgery went from 46.0% to 46.5%, and same-day surgery from 13.3% to 12.4%. Unchanged trends were confirmed by ITSA after controlling for the 32-week time-series observed the year before. In the second week of March 2020, there was a borderline significant decrease in weekly hospital admissions for hip fractures as compared with that of the same week of March 2019 (-1.95 per 100 000, 95% CI = -4.10 to 0.21, P value = .075), followed by a weekly significant increase in the hospitalization rate (+0.14 per 100 000, 95% CI = 0.01 to 0.27, P value = .039), although the difference-in-differences of slopes failed to achieve statistical significance (0.19 per 100 000, 95% CI = -0.03 to 0.41, P value = .090).

CONCLUSION: Our study shows that the timing of hip-fracture surgery was unchanged during the lockdown period. This suggests that the healthcare systems can be resilient and able to guarantee a high-quality and safe healthcare to hip-fracture patients, even in the most challenging working conditions.

PMID:34523862 | DOI:10.34172/ijhpm.2021.103