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Nevin Manimala Statistics

Clinical outcomes of modifying hypertension treatment intensity in older adults treated to low blood pressure

J Am Geriatr Soc. 2021 Jun 7. doi: 10.1111/jgs.17295. Online ahead of print.

ABSTRACT

BACKGROUND/OBJECTIVES: Hypertension treatment reduces cardiovascular events. However, uncertainty remains about benefits and harms of deintensification or further intensification of antihypertensive medication when systolic blood pressure (SBP) is tightly controlled in older multimorbid patients, because of their frequent exclusion in trials. We assessed the association of hypertension treatment deintensification or intensification with clinical outcomes in older adults with tightly controlled SBP.

DESIGN: Longitudinal cohort study (2011-2013) with 9-month follow-up.

SETTING: U.S.-nationwide primary care Veterans Health Administration healthcare system.

PARTICIPANTS: Veterans aged 65 and older with baseline SBP <130 mmHg and ≥1 antihypertensive medication during ≥2 consecutive visits (N = 228,753).

EXPOSURE: Deintensification or intensification, compared with stable treatment.

MAIN OUTCOMES AND MEASURES: Cardiovascular events, syncope, or fall injury, as composite and distinct outcomes, within 9 months after exposure. Adjusted logistic regression and inverse probability of treatment weighting (IPTW, sensitivity analysis).

RESULTS: Among 228,753 patients (mean age 75 [SD 7.5] years), the composite outcome occurred in 11,982/93,793 (12.8%) patients with stable treatment, 14,768/72,672 (20.3%) with deintensification, and 11,821/62,288 (19.0%) with intensification. Adjusted absolute outcome risk (95% confidence interval) was higher for deintensification (18.3% [18.1%-18.6%]) and intensification (18.7% [18.4%-19.0%]), compared with stable treatment (14.8% [14.6%-15.0%]), p < 0.001 for both effects in the multivariable model). Deintensification was associated with fewer cardiovascular events than intensification. At baseline SBP <95 mmHg, cardiovascular event risk was similar for deintensification and stable treatment, and fall risk lower for deintensification than intensification. IPTW yielded similar results. Mean follow-up SBP was 124.1 mmHg for stable treatment, 125.1 mmHg after deintensification (p < 0.001), and 124.0 mmHg after intensification (p < 0.001).

CONCLUSION: Antihypertensive treatment deintensification in older patients with tightly controlled SBP was associated with worse outcomes than continuing same treatment intensity. Given higher mortality among patients with treatment modification, confounding by indication may not have been fully corrected by advanced statistical methods for observational data analysis.

PMID:34097300 | DOI:10.1111/jgs.17295

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Nevin Manimala Statistics

Long-Term Results of One Anastomosis Gastric Bypass: a Single Center Experience with a Minimum Follow-Up of 10 Years

Obes Surg. 2021 Jun 7. doi: 10.1007/s11695-021-05455-1. Online ahead of print.

ABSTRACT

PURPOSE: The purpose of this study was to evaluate the efficacy and safety of the OAGB at least 10 years after surgery.

MATERIAL AND METHODS: We retrospectively reviewed our prospectively collected data on consecutive morbid patients with obesity receiving OAGB from January 2005 to December 2007.

RESULTS: A total of 385 patients met the inclusion criteria. The mean follow-up was 149 months. Of all patients, 52% underwent OAGB as a primary procedure and 48% as a revisional procedure. At the 10-year follow-up, the mean body mass index (BMI) was 30.7 ± 11.8, the mean %TWL was 33.4 ± 10.6, and the mean %EWL was 64.1 ± 24.6. We did not find a significant statistical difference in terms of weight loss between primary OAGB and secondary OAGB. In total, 43% of patients achieved a %EWL greater than 75%, while 29% of the patients had an EWL% that was below 50%. All of the comorbidities related to obesity showed a high improvement or fully resolved. Early complications occurred in 9 patients (2.3%), while the overall rate of late complications was 17.1%. Nineteen patients (4.9%) developed an ulcer at the gastrojejunal anastomosis level, nine patients (2.3%) were re-hospitalized for major malnutrition, thirty-eight patients (9.8%) showed a postoperative biliary reflux, and five patients (2.7%) experienced severe anemia, which required several hospitalizations for iron I.V. supplementation.

CONCLUSION: According to results of the present study, we believe that OAGB has shown to be a technique with a reasonable balance between long-term efficacy and undesirable sequelae.

PMID:34097238 | DOI:10.1007/s11695-021-05455-1

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Nevin Manimala Statistics

Environmental Kuznets curve in Southeastern Europe: the role of urbanization and energy consumption

Environ Sci Pollut Res Int. 2021 Jun 7. doi: 10.1007/s11356-021-14732-6. Online ahead of print.

ABSTRACT

This paper investigates the dynamic short-term and long-term relationships among real GDP per capita, energy consumption, urbanization, and carbon dioxide emissions within the framework of the environmental Kuznets curve (EKC) hypothesis for Southeastern Europe (SEE) from 1997 to 2014. The evidence highlights an inverted U-shaped nexus between real GDP per capita and carbon dioxide emissions (i.e., the EKC hypothesis is verified in the long-run in the sample as a whole). The short-run estimates provide evidence of inverted U-shaped EKC only for Greece and Moldova. Two-way causal relationship between urbanization and pollutant emission was also established in the short-run, as well as one-way causality flowing from real GDP per capita to pollutant emission. The coefficients with the real GDP per capita and energy consumption are negative and statistically significant in the long-term. These findings indicate the existence of an error correction mechanism that drives the observed variables back to their equilibrium. Moreover, the findings show that the consistent increase in energy consumption has not reduced environmental pressures.

PMID:34097219 | DOI:10.1007/s11356-021-14732-6

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Nevin Manimala Statistics

A unified model-implied instrumental variable approach for structural equation modeling with mixed variables

Psychometrika. 2021 Jun 7. doi: 10.1007/s11336-021-09771-4. Online ahead of print.

ABSTRACT

The model-implied instrumental variable (MIIV) estimator is an equation-by-equation estimator of structural equation models that is more robust to structural misspecifications than full information estimators. Previous studies have concentrated on endogenous variables that are all continuous (MIIV-2SLS) or all ordinal . We develop a unified MIIV approach that applies to a mixture of binary, ordinal, censored, or continuous endogenous observed variables. We include estimates of factor loadings, regression coefficients, variances, and covariances along with their asymptotic standard errors. In addition, we create new goodness of fit tests of the model and overidentification tests of single equations. Our simulation study shows that the proposed MIIV approach is more robust to structural misspecifications than diagonally weighted least squares (DWLS) and that both the goodness of fit model tests and the overidentification equations tests can detect structural misspecifications. We also find that the bias in asymptotic standard errors for the MIIV estimators of factor loadings and regression coefficients are often lower than the DWLS ones, though the differences are small in large samples. Our analysis shows that scaling indicators with low reliability can adversely affect the MIIV estimators. Also, using a small subset of MIIVs reduces small sample bias of coefficient estimates, but can lower the power of overidentification tests of equations.

PMID:34097200 | DOI:10.1007/s11336-021-09771-4

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Nevin Manimala Statistics

Replicating a GWAS: two novel candidate markers for oligospermia in Greek population

Mol Biol Rep. 2021 Jun 7. doi: 10.1007/s11033-021-06470-2. Online ahead of print.

ABSTRACT

Genome-wide association studies have paved the way for the discovery of new markers regarding many diseases, including male infertility. A previous study on Caucasians highlighted 172 polymorphisms for their putative association with male infertility and we attempted to replicate these findings on our dataset comprising of Greek male individuals (n = 360). We retrieved 59 out of 172 polymorphisms and tested for all association models on 278 normospermic men and 82 patients with an abnormal seminogram, later separated into oligozoospermic and asthenozoospermic groups. Our findings indicate that two SNPs (rs2296225 in KIF17, rs7224496 in SMYD4) are associated with male infertility in the Greek population and have not been recorded in literature as of yet. These novel markers need further validation via additional studies and an increased individual number. All in all, replication studies, possess the power to validate existing polymorphisms found across all population and thus increase both statistical significance as well as identify novel potentially diagnostic markers.

PMID:34097203 | DOI:10.1007/s11033-021-06470-2

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Nevin Manimala Statistics

Collider Bias in Administrative Workers’ Compensation Claims Data: A Challenge for Cross-Jurisdictional Research

J Occup Rehabil. 2021 Jun 7. doi: 10.1007/s10926-021-09988-1. Online ahead of print.

ABSTRACT

PURPOSE: Workers’ compensation claims consist of occupational injuries severe enough to meet a compensability threshold. Theoretically, systems with higher thresholds should have fewer claims but greater average severity. For research that relies on claims data, particularly cross-jurisdictional comparisons of compensation systems, this results in collider bias that can lead to spurious associations confounding analyses. In this study, I use real and simulated claims data to demonstrate collider bias and problems with methods used to account for it.

METHODS: Using Australian claims data, I used a linear regression to test the association between claim rate and mean disability durations across Statistical Areas. Analyses were repeated with nesting by state/territory to account for variations in compensability thresholds across compensation systems. Both analyses are repeated on left-censored data. Simulated claims data are analysed with Cox survival analyses to illustrate how left-censoring can reverse effects.

RESULTS: The claim rate within a Statistical Area was inversely associated with disability duration. However, this reversed when Statistical Areas were nested by state/territory. Left-censoring resulted in an attenuation of the unnested association to non-significance, while the nested association remained significantly positive. Cox regressions with simulated claims data demonstrated how left-censoring can reverse effects.

CONCLUSIONS: Collider bias can seriously confound work disability research, particularly cross-jurisdictional comparisons. Work disability researchers must grapple with this challenge by using appropriate study designs and analytical approaches, and considering how it affects the interpretation of results.

PMID:34097183 | DOI:10.1007/s10926-021-09988-1

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Nevin Manimala Statistics

Learning curve of single-incision laparoscopic totally extraperitoneal repair (SILTEP) for inguinal hernia

Hernia. 2021 Jun 7. doi: 10.1007/s10029-021-02431-7. Online ahead of print.

ABSTRACT

PURPOSE: Laparoscopic totally extraperitoneal hernia repair (TEP) is a widely used treatment for inguinal hernia. Single-incision laparoscopic TEP (SILTEP) has attracted the attention of several surgeons, given its superior cosmetic results and patient satisfaction, as well as comparable outcomes to multiport surgery. Nonetheless, no relevant studies have evaluated the learning curve (LC) of SILTEP in terms of both operation time (OT) and surgical failure. Therefore, we aimed to investigate the LC of SILTEP for inguinal hernia.

METHODS: Medical records of 180 patients who underwent SILTEP performed by a single surgeon from a single institution between October 2012 and November 2017 were retrospectively reviewed. The LC was analyzed using the moving average method and cumulative sum control chart (CUSUM) for OT and surgical failure. Surgical failure was defined as the need for additional ports, open conversion, severe postoperative complications (Clavien-Dindo ≥ IIIa), and recurrence. Eight patients who underwent combined surgery or bilateral hernia repair were excluded from the OT analysis.

RESULTS: From CUSUM graphs, the study period was divided into three phases: OT-phases 1 (1st-32nd), 2 (33rd-83rd), and 3 (84th-172nd) for OT and failure-phases 1 (1st-29th), 2 (30th-58th), and 3 (59th-180th) for surgical failure. Mean OTs were statistically different in the three OT phases (64.6 vs. 50.8 vs. 35.2 min; p < 0.001). Open conversion (31.0% vs. 0% vs. 2.5%) and additional port insertion (6.9% vs. 24.1% vs. 2.5%) stabilized consecutively at failure-phases 2 and 3 (p < 0.001). Surgical failure rates decreased to 5.7% by failure-phase 3 (37.9% vs. 24.1% vs. 5.7%; p < 0.001).

CONCLUSION: For an experienced laparoscopic surgeon, we estimated that approximately 60 cases are needed to overcome the LC for SILTEP in terms of both reducing OT and achieving a surgical failure rate < 10%. Further proficiency could be achieved after approximately 85 SILTEP procedures with a stable OT of approximately 35 min.

PMID:34097186 | DOI:10.1007/s10029-021-02431-7

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Nevin Manimala Statistics

Is surgery a risk factor for contralateral recurrence pneumothorax in adolescent with primary spontaneous pneumothorax?

Gen Thorac Cardiovasc Surg. 2021 Jun 7. doi: 10.1007/s11748-021-01663-9. Online ahead of print.

ABSTRACT

OBJECTIVES: Controversy exists regarding the justification of primary surgery in primary spontaneous pneumothorax, and surgery is not free from recurrence. We hypothesized that surgery is a risk factor for contralateral recurrence pneumothorax in adolescent.

METHODS: We performed a retrospective cohort study of 163 adolescent with pneumothorax who were treated conservatively with chest tube (n = 100) or chest tube followed by video-assisted thoracoscopic surgery (n = 63) from January 2009 through December 2017.

RESULTS: Ipsilateral recurrence was significantly more common following conservative treatment than surgical treatment (25.0 vs. 3.2%, P < 0.001), while contralateral recurrence was more common in the surgical group than in the conservative group (15.9 vs. 6.0%, P = 0.039). The rates of second episode pneumothorax did not significantly differ between the two treatment groups (P = 0.092). Univariate analysis identified that patients who were treated conservatively had greater risk of ipsilateral recurrence (P = 0.002), while those who proceeded to surgery had greater risk of contralateral recurrence (P = 0.046). No predictors for second episode pneumothorax were found.

CONCLUSION: To avoid over treatment, we recommend that conservative treatment should be the superior option and CT scan should not be a routine examination in adolescent with their first episode of PSP.

PMID:34097199 | DOI:10.1007/s11748-021-01663-9

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Nevin Manimala Statistics

Validating the regional estimates of changes in soil organic carbon by using the data from paired-sites: the case study of Mediterranean arable lands

Carbon Balance Manag. 2021 Jun 7;16(1):19. doi: 10.1186/s13021-021-00182-7.

ABSTRACT

BACKGROUND: Legacy data are unique occasions for estimating soil organic carbon (SOC) concentration changes and spatial variability, but their use showed limitations due to the sampling schemes adopted and improvements may be needed in the analysis methodologies. When SOC changes is estimated with legacy data, the use of soil samples collected in different plots (i.e., non-paired data) may lead to biased results. In the present work, N = 302 georeferenced soil samples were selected from a regional (Sicily, south of Italy) soil database. An operational sampling approach was developed to spot SOC concentration changes from 1994 to 2017 in the same plots at the 0-30 cm soil depth and tested.

RESULTS: The measurements were conducted after computing the minimum number of samples needed to have a reliable estimate of SOC variation after 23 years. By applying an effect size based methodology, 30 out of 302 sites were resampled in 2017 to achieve a power of 80%, and an α = 0.05. A Wilcoxon test applied to the variation of SOC from 1994 to 2017 suggested that there was not a statistical difference in SOC concentration after 23 years (Z = – 0.556; 2-tailed asymptotic significance = 0.578). In particular, only 40% of resampled sites showed a higher SOC concentration than in 2017.

CONCLUSIONS: This finding contrasts with a previous SOC concentration increase that was found in 2008 (75.8% increase when estimated as differences of 2 models built with non-paired data), when compared to 1994 observed data (Z = – 9.119; 2-tailed asymptotic significance < 0.001). This suggests that the use of legacy data to estimate SOC concentration dynamics requires soil resampling in the same locations to overcome the stochastic model errors. Further experiment is needed to identify the percentage of the sites to resample in order to align two legacy datasets in the same area.

PMID:34097152 | DOI:10.1186/s13021-021-00182-7

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Nevin Manimala Statistics

Comparison of short-stem versus conventional stem for hip arthroplasty in patients younger than 60 years: 7-14 years follow-up

Eur J Orthop Surg Traumatol. 2021 Jun 7. doi: 10.1007/s00590-021-03017-w. Online ahead of print.

ABSTRACT

PURPOSE: Short-stem prostheses in hip arthroplasty have emerged as an alternative to conventional stems, especially in younger patients. The purpose of this study was to compare functional and radiological results of a short metaphyseal fitting cementless stem versus a conventional stem implant, in patients younger than 60 years.

METHODS: All patients operated from January 2006 to April 2013 were included, obtaining a minimum follow-up of 7 years. Harris Hip Score (HHS) and SF-36 (quality of life) questionnaires were applied and the presence of “thigh pain” was specifically assessed. We also compared complication rate, revision rate and average prosthesis survival. Femoral stress shielding (Gruen scale), stem subsidence, varus-valgus tilt and implant stability (Engh scale) were also compared.

RESULTS: A total of 101 short-stem and 74 conventional arthroplasties were included, with an average follow-up of 9.82 (7-14) years. HHS functional score and SF-36 were excellent in both implants and no significant difference between them (p > 0.05) was found. However, “thigh pain” was present in 7 patients with conventional stems and none with short-stems (p < 0.001). The survival rate at 13 years was 99%, for both implants, and no significant differences were found between them (χ2(2) = 0.178; p = 0.673). Conventional stems had stress shielding at the greater trochanter in 72% of the cases and 43% at the calcar, being statistically superior (p < 0.001) to the stress shielding observed in the short stems.

CONCLUSION: According to our results, this short-stem seems to allow preservation of bone stock, with decreased stress shielding and also a lower incidence of thigh pain compared to conventional stems.

LEVEL OF EVIDENCE: Level III retrospective comparative study.

PMID:34097153 | DOI:10.1007/s00590-021-03017-w