Methodological challenges in the evaluation of prognostic factors in breast cancer

Training-Load Management Ambiguities and Weak Logic: Creating Potential Consequences in Sport Training and Performance

BACKGROUND

The optimization of athlete training load is not a new concept; however in recent years, the concept of "load management" is one of the most widely studied and divisive topics in sports science and medicine.

PURPOSE

Discuss the challenges faced by sports when utilizing training load monitoring and management, with a specific focus on the use of data to inform load management guidelines and policies/mandates, their consequences, and how we move this field forward.

CHALLENGES

While guidelines can theoretically help protect athletes, overzealous and overcautious guidelines may restrict an athlete's preparedness, negatively influence performance, and increase injury risk. Poor methods, wrong interpretation of study findings, and faulty logic do not allow for systematic scientific evaluations to inform guidelines. Practical Solutions: Guidelines and mandates should be developed through a systematic research process with stronger research designs and clear research questions. Collaborating with statistical and epidemiological experts is essential. Implementing open science principles and sharing all sports training load data increase transparency and allow for more rapid and valid advancements in knowledge. Practitioners should incorporate multiple data streams and consider individual athlete responses, rather than applying broad guidelines based on average data.

CONCLUSION

Many current training load guidelines and mandates in sports come from good intentions; however, they are arbitrary without sound knowledge of the underlying scientific principles or methods. Common sense guidelines are helpful when there is sparse literature, but they should be careful to avoid arbitrarily choosing findings from weak research. Without precise scientific inquiries, implementing training load interventions or guidelines can have negative implications.

Factors associated with pathologic myopia onset and progression: A systematic review and meta-analysis

PURPOSE

To synthesise evidence across studies on factors associated with pathologic myopia (PM) onset and progression based on the META-analysis for Pathologic Myopia (META-PM) classification framework.

METHODS

Findings from six longitudinal studies (5-18 years) were narratively synthesised and meta-analysed, using odds ratio (OR) as the common measure of association. All studies adjusted for baseline myopia, age and sex at a minimum. The quality of evidence was rated using the Grades of Recommendation, Assessment, Development and Evaluation framework.

RESULTS

Five out of six studies were conducted in Asia. There was inconclusive evidence of an independent effect (or lack thereof) of ethnicity and sex on PM onset/progression. The odds of PM onset increased with greater axial length (pooled OR: 2.03; 95% CI: 1.71-2.40; p < 0.001), older age (pooled OR: 1.07; 1.05-1.09; p < 0.001) and more negative spherical equivalent refraction, SER (OR: 0.77; 0.68-0.87; p < 0.001), all of which were supported by an acceptable level of evidence. Fundus tessellation was found to independently increase the odds of PM onset in a population-based study (OR: 3.02; 2.58-3.53; p < 0.001), although this was only supported by weak evidence. There was acceptable evidence that greater axial length (pooled OR: 1.23; 1.09-1.39; p < 0.001), more negative SER (pooled OR: 0.87; 0.83-0.92; p < 0.001) and higher education level (pooled OR: 3.17; 1.36-7.35; p < 0.01) increased the odds of PM progression. Other baseline factors found to be associated with PM progression but currently supported by weak evidence included age (pooled OR: 1.01), severity of myopic maculopathy (OR: 3.61), intraocular pressure (OR: 1.62) and hypertension (OR: 0.21).

CONCLUSIONS

Most PM risk/prognostic factors are not supported by an adequate evidence base at present (an indication that PM remains understudied). Current factors for which an acceptable level of evidence exists (limited in number) are unmodifiable in adults and lack personalised information. More longitudinal studies focusing on uncovering modifiable factors and imaging biomarkers are warranted.

Previous Knee Surgery, Anteromedial Portal Drilling, Quadriceps Tendon Autograft, and Meniscal Involvement Associated With Delayed Return to Sport After Anterior Cruciate Ligament Reconstruction in Amateur Athletes

Purpose

To identify prognostic factors associated with a delayed return-to-sport (RTS) time in amateur athletes who return to full participation after a primary isolated anterior cruciate ligament (ACL) reconstruction.

Methods

A retrospective review was performed among athletes who underwent ACL reconstruction between October 2014 and October 2021. Inclusion criteria were any amateur athletes with an ACL reconstruction who had a documented RTS and greater than 1-year follow-up. Nonathletes, those with multiligamentous knee injury, and those missing documented RTS timelines were excluded. RTS was defined as participation in athletics at a level equivalent to or greater than the preinjury level participation. Demographic and prognostic factors, including previous knee surgery, meniscal involvement, level of participation, surgical approach, and graft type, were recorded along with RTS time and analyzed via Poisson regression.

Results

In total, 91 athletes, average age 18.8 (± 6.7) years, who underwent ACL reconstruction at a single institution from 2014 to 2021 were identified with an average follow-up time of 4.6 (± 2.5) years (range 1.1, 9.0). Meniscal involvement (1.11; 95% confidence interval [CI] 1.08-1.15, P < .001) and previous knee surgery (1.43; 95% CI 1.29-1.58; P < .001) were related to a delayed RTS. Quadriceps tendon and bone-patellar tendon-bone autografts, as well as allograft, showed a significant association with a longer RTS time when compared with hamstring autograft (1.16, 95% CI 1.13-1.20, P < .001; 1.04, 95% CI 1.01-1.07, P = .020; 1.11, 95% CI 1.03-1.19, P = .004, respectively), as did anteromedial portal drilling, when compared with the outside in approach for femoral drilling (1.19, 95% CI 1.16-1.23, P < .001).

Conclusions

Previous knee surgery, anteromedial femoral drilling, quadriceps tendon autograft, and meniscus tear were most associated with a delayed timeline for RTS among young athletes who were able to return.

Level of Evidence

Level IV, prognostic case series.

Biomarkers in clinical epidemiology studies

This paper discusses the use of biomarkers in clinical practice and biomedical research. Biomarkers are measurable characteristics that can be used to indicate the presence or absence of a disease or to track the progression of a disease. They can also be used to predict how a patient will respond to a particular treatment. Biomarkers have enriched clinical practice and disease prognosis by providing measurable characteristics that indicate biological processes. They offer valuable insights into disease susceptibility, progression, and treatment response, aiding drug development and personalized medicine. However, developing and implementing biomarkers come with challenges that must be addressed. Rigorous testing, standardization of assays, and consideration of ethical factors are crucial in ensuring the reliability and validity of biomarkers. Reliability is vital in biomarker research. It ensures accurate measurements by preventing biases and facilitating robust correlations with outcomes. Conversely, validation examines which and how many biomarkers correspond to theoretical constructs and external criteria, establishing their predictive value. Multiple biomarkers are sometimes necessary to represent the complex relationship between exposure and disease outcomes accurately. Susceptibility factors are pivotal in disease states' complex interaction among genetic and environmental factors. Gaining a comprehensive understanding of these factors is essential for effectively interpreting biomarker data and maximizing their clinical usefulness. Using well-validated biomarkers can improve diagnoses, more effective treatment evaluations, and enhanced disease prediction. This, in turn, will contribute to better patient outcomes and drive progress in medicine.

Phases of methodological research in biostatistics-Building the evidence base for new methods

Although new biostatistical methods are published at a very high rate, many of these developments are not trustworthy enough to be adopted by the scientific community. We propose a framework to think about how a piece of methodological work contributes to the evidence base for a method. Similar to the well-known phases of clinical research in drug development, we propose to define four phases of methodological research. These four phases cover (I) proposing a new methodological idea while providing, for example, logical reasoning or proofs, (II) providing empirical evidence, first in a narrow target setting, then (III) in an extended range of settings and for various outcomes, accompanied by appropriate application examples, and (IV) investigations that establish a method as sufficiently well-understood to know when it is preferred over others and when it is not; that is, its pitfalls. We suggest basic definitions of the four phases to provoke thought and discussion rather than devising an unambiguous classification of studies into phases. Too many methodological developments finish before phase III/IV, but we give two examples with references. Our concept rebalances the emphasis to studies in phases III and IV, that is, carefully planned method comparison studies and studies that explore the empirical properties of existing methods in a wider range of problems.

Prognostic value of blood-based protein biomarkers in non-small cell lung cancer: A critical review and 2008-2022 update

BACKGROUND

Therapeutic possibilities for non-small cell lung cancer (NSCLC) have considerably increased during recent decades.

OBJECTIVE

To summarize the prognostic relevance of serum tumor markers (STM) for early and late-stage NSCLC patients treated with classical chemotherapies, novel targeted and immune therapies.

METHODS

A PubMed database search was conducted for prognostic studies on carcinoembryonic antigen (CEA), cytokeratin-19 fragment (CYFRA 21-1), neuron-specific enolase, squamous-cell carcinoma antigen, progastrin-releasing-peptide, CA125, CA 19-9 and CA 15-3 STMs in NSCLC patients published from 2008 until June 2022.

RESULTS

Out of 1069 studies, 141 were identified as meeting the inclusion criteria. A considerable heterogeneity regarding design, patient number, analytical and statistical methods was observed. High pretherapeutic CYFRA 21-1 levels and insufficient decreases indicated unfavorable prognosis in many studies on NSCLC patients treated with chemo-, targeted and immunotherapies or their combinations in early and advanced stages. Similar results were seen for CEA in chemotherapy, however, high pretherapeutic levels were sometimes favorable in targeted therapies. CA125 is a promising prognostic marker in patients treated with immunotherapies. Combinations of STMs further increased the prognostic value over single markers.

CONCLUSION

Protein STMs, especially CYFRA 21-1, have prognostic potential in early and advanced stage NSCLC. For future STM investigations, better adherence to comparable study designs, analytical methods, outcome measures and statistical evaluation standards is recommended.

Description, Prediction, and Causation in Sport and Exercise Medicine Research: Resolving the Confusion to Improve Research Quality and Patient Outcomes

SYNOPSIS: Researchers often assign a label (such as a risk factor or predictor) to a characteristic that is statistically associated with an outcome (such as future injury). Labeling signifies that the characteristic has an established clinical value. More often than not, these labels are assigned prematurely and haphazardly. The rampant practice conflates research goals, the ultimate clinical value of the findings, and many risk factors/predictors that may not warrant the label. To address these issues and improve injury prevention research, we (1) outline the problem; (2) clarify the key differences between the research goals of description, causation, and prediction/prognosis (along with labeling conventions); (3) differentiate the clinical implications for each label; and (4) frame an appropriate scientific process to follow before applying a label. J Orthop Sports Phys Ther 2023;53(7):1-7. Epub: 26 April 2023. doi:10.2519/jospt.2023.11773.

REMARK guidelines for tumour biomarker study reporting: a remarkable history

In 2005, several experts in tumor biomarker research publishe the REporting recommendations for Tumor MARKer prognostic studies (REMARK) criteria. Coupled with the subsequent Biospecimen Reporting for Improved Study Quality (BRISQ) criteria, these initiatives provide a framework for transparently reporting of the methods of study conduct and analyses.

Can prognostic factors for indirect muscle injuries in elite football (soccer) players be identified using data from preseason screening? An exploratory analysis using routinely collected periodic health examination records

BACKGROUND

In elite football, periodic health examination (PHE) may be useful for injury risk prediction.

OBJECTIVE

To explore whether PHE-derived variables are prognostic factors for indirect muscle injuries (IMIs) in elite players.

DESIGN

Retrospective cohort study.

SETTING

An English Premier League football club.

PARTICIPANTS

134 outfield elite male players, over 5 seasons (1 July 2013-19 May 2018).

OUTCOME AND ANALYSIS

The outcome was any time-loss, lower extremity index IMI (I-IMI). Prognostic associations were estimated using odds ratios (ORs) and corresponding statistical significance for 36 variables, derived from univariable and multivariable logistic regression models. Missing data were handled using multiple imputation. Non-linear associations were explored using fractional polynomials.

RESULTS

During 317 participant-seasons, 138 I-IMIs were recorded. Univariable associations were determined for previous calf IMI frequency (OR 1.80, 95% CI 1.09 to 2.97), hamstring IMI frequency (OR 1.56, 95% CI 1.17 to 2.09), if the most recent hamstring IMI occurred >12 months but <3 years prior to PHE (OR 2.95, 95% CI 1.51 to 5.73) and age (OR 1.12 per 1-year increase, 95% CI 1.06 to 1.18). Multivariable analyses showed that if a player's most recent previous hamstring IMI was >12 months but <3 years prior to PHE (OR 2.24, 95% CI 1.11 to 4.53), this was the only variable with added prognostic value over and above age, which was a confirmed prognostic factor (OR 1.12 per 1-year increase, 95% CI 1.05 to 1.18). Allowing non-linear associations conferred no advantage over linear associations.

CONCLUSION

PHE has limited use for injury risk prediction. Most variables did not add prognostic value over and above age, other than if a player experienced a hamstring IMI >12 months but <3 years prior to PHE. However, the precision of this prognostic association should be confirmed in future.

TRIAL REGISTRATION NUMBER

NCT03782389.

Low-Intensity Adjuvant Chemotherapy for Breast Cancer in Older Women: Results From the Prospective Multicenter HOPE Trial

PURPOSE

Older women with high-risk early breast cancer (EBC) benefit from adjuvant chemotherapy, but their treatment is frequently complicated by toxic side effects, resulting in dose reductions and delays. This makes it challenging for oncologists to maintain a relative dose intensity (RDI) ≥ 85%, as recommended for optimal curative-intent treatment. Understanding which women are at risk of receiving suboptimal RDI may inform treatment discussions and guide early, targeted supportive care or geriatric comanagement interventions.

METHODS

This was a prespecified secondary analysis of the HOPE trial, which enrolled women age ≥ 65 years with EBC initiating neoadjuvant or adjuvant chemotherapy. RDI was calculated as the ratio of delivered to planned chemotherapy dose intensity. The primary outcome was low RDI, defined as RDI < 85%. Multivariable logistic regression with stepwise selection was used to evaluate the association between baseline variables (demographic, clinical, and geriatric assessment) and low RDI. Survival probability was estimated using the Kaplan-Meier method, and the log-rank test was used to compare overall survival.

RESULTS

Three hundred twenty-two patients (median age at diagnosis, 70 years; range, 65-86 years) were included. The median follow-up was 4 years. Sixty-six patients (21%) had a low RDI. Age ≥ 76 years (odds ratio [OR], 2.57; 95% CI, 1.12 to 5.91; P = .03), lower performance status (OR, 4.32; 95% CI, 1.98 to 9.42; P < .001), and use of anthracycline-based or cyclophosphamide, methotrexate, and fluorouracil regimens (OR, 3.47; 95% CI, 1.71 to 7.05; P < .001) were associated with low RDI. The 5-year overall survival probability was 0.80 versus 0.91 in patients with RDI < 85 versus ≥ 85%, respectively (log-rank P = .02).

CONCLUSION

One in five older patients with EBC treated with standard chemotherapy received low RDI and had inferior survival outcomes. Older patients at risk for low RDI should be identified and targeted upfront before initiating chemotherapy.

Comparative Effectiveness of Immune Checkpoint Inhibitors vs Chemotherapy in Patients With Metastatic Colorectal Cancer With Measures of Microsatellite Instability, Mismatch Repair, or Tumor Mutational Burden

Importance

The KEYNOTE-177 trial demonstrated that patients with metastatic colorectal cancer (MCRC) with high microsatellite instability (MSI-H) and/or mismatch repair deficiency (DMMR) have better outcomes when receiving first-line immune checkpoint inhibitors (ICIs) compared with chemotherapy. Data on performance of ICIs in patients with MCRC in standard practice settings remain limited, and direct MMR vs MSI outcome association comparisons are lacking.

Objective

To validate MSI (determined by next-generation sequencing [NGS]) as a biomarker of ICI effectiveness among patients with MCRC in standard practice settings and examine the association of MSI assessed by NGS, DMMR by immunohistochemistry, and tumor mutational burden (cutoff, 10 mutations/megabase) with ICI outcomes.

Design, Setting, and Participants

This comparative effectiveness research study of outcomes in prospectively defined biomarker subgroups used data from a deidentified clinicogenomic database and included patients who received Foundation Medicine testing (FoundationOne or FoundationOne CDx) during routine clinical care at approximately 280 US academic or community-based cancer clinics between March 2014 and December 2021. The population included 1 cohort of patients with MSI-H MCRC who received first-line ICIs or chemotherapy and a second cohort who received ICIs in any line of therapy (LOT) for biomarker examination.

Exposures

ICI therapy or chemotherapy assigned at physician discretion without randomization.

Main Outcomes and Measures

The main outcomes were time to next treatment (TTNT), progression-free survival (PFS), and overall survival (OS). Hazard ratios were adjusted for known prognostic imbalances. Comparisons of explanatory power used the likelihood ratio test.

Results

A total of 138 patients (median age, 67.0 years [IQR, 56.2-74.0 years]; 73 [52.9%] female) with MSI-H MCRC received first-line ICIs or chemotherapy. A total of 182 patients (median age, 64.5 years [IQR, 55.2-72.0]; 98 [53.8%] female) received ICIs in any LOT. Patients receiving first-line ICIs vs chemotherapy had longer TTNT (median, not reached [NR] vs 7.23 months [IQR, 6.21-9.72 months]; adjusted hazard ratio [AHR], 0.17; 95% CI, 0.08-0.35; P < .001), PFS (median, 24.87 months [IQR, 19.10 months to NR] vs 5.65 months [IQR, 4.70-8.34 months]; AHR, 0.31; 95% CI, 0.18-0.52; P < .001), and OS (median, NR vs 24.1 months [IQR, 13.90 months to NR]; HR, 0.45; 95% CI, 0.23-0.88; P = .02). MSI added to DMMR better anticipated TTNT and PFS in patients receiving ICIs than DMMR alone. The same was not observed when DMMR evaluation was added to MSI.

Conclusions and Relevance

In this comparative effectiveness research study, MSI assessed by NGS robustly identified patients with favorable outcomes on first-line ICIs vs chemotherapy and appeared to better anticipate ICI outcomes compared with DMMR.

Factors Associated With Successful Video-Assisted Thoracoscopic Surgery for Traumatic Hemothorax in Children: A Cross-Sectional Study

INTRODUCTION

Due to the rarity of traumatic hemothorax in children, no studies have evaluated factors associated with successful video-assisted thoracoscopic surgery (VATS) as definitive management.

METHODS

We conducted an exploratory cross-sectional analysis of pediatric patients in the Trauma Quality Programs database from 2008 to 2017 with traumatic hemothorax managed with primary VATS. Those with early resuscitative thoracotomy for cardiac arrest were excluded. We stratified patients by blunt or penetrating mechanism and estimated absolute differences (ADs) and 95% confidence intervals (CIs) to identify factors associated with successful VATS without conversion to thoracotomy or reoperation.

RESULTS

A total of 293 patients were eligible. Among 184 penetrating injuries, 150 (82%) underwent successful VATS, 6 (3%) required reoperation, and 28 (15%) converted to thoracotomy. Diaphragmatic injuries (AD = -28, 95% CI = -46 to -10) and rib fractures (AD = 12, 95% CI = 1 to 23) had the strongest negative and positive associations (respectively) with successful VATS. There were 109 blunt injuries: 86 (79%) underwent successful VATS, 6 (6%) required reoperation, and 17 (16%) converted to thoracotomy. Moderate or severe head injury (AD = -15, 95% CI = -32 to 2), injury severity score >15 (AD = -19, 95% CI = -33 to -5), and the presence of diaphragmatic injury (AD = -38, 95% CI = -71 to -4) had the strongest negative associations with successful VATS.

CONCLUSIONS

Some children with traumatic hemothorax can be successfully managed with VATS. For penetrating mechanism, diaphragmatic injuries were associated with less success, while rib fractures were associated with more success. For blunt mechanism, diaphragmatic injuries, injury severity score >15, or moderate or severe head injury were associated with less success.

The association between person and fracture characteristics with patient reported outcome after ankle fractures in adults: A systematic review

BACKGROUND

The incidence of ankle fractures is increasing and the clinical outcome is highly variable.

QUESTION

What person and fracture characteristics are associated with patient reported outcomes after surgically or conservatively managed ankle fractures in adults?

DATA SOURCES

Medline, EMBASE, and Allied and Complimentary Health Medical Database (AMED) databases were searched from the earliest available date until 16th July 2020.

STUDY SELECTION

Prognostic factors studies recruiting adults of age 18 years or older with a radiologically confirmed ankle fracture, and evaluating function, symptoms and quality of life by patient reported outcome measures, were included.

STUDY APPRAISAL/SYNTHESIS METHODS

Risk of bias of individual studies was assessed by the Quality in Prognostic Factors Studies tool. Correlation coefficients were calculated and data were analysed using narrative synthesis.

RESULTS

Fifty-one phase 1 explanatory studies with 6177 participants met the inclusion criteria. Thirty-one studies were rated as high risk of bias using the Quality in Prognostic Factors Studies tool. There was low quality evidence that age, body mass index, American Society of Anesthesiologists classification and pre-injury mobility were associated with function, and low to moderate quality evidence that age, smoking and American Society of Anesthesiologists classification were associated with quality of life. No person characteristics were associated with symptoms and no fracture characteristics were associated with any outcomes.

CONCLUSION

There was low to moderate quality evidence that person characteristics may be associated with patient reported function and quality of life following ankle fracture.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42020184830.

Mammographic density, endocrine therapy and breast cancer risk: a prognostic and predictive biomarker review

BACKGROUND

Endocrine therapy is effective at preventing or treating breast cancer. Some forms of endocrine therapy have been shown to reduce mammographic density. Reduced mammographic density for women receiving endocrine therapy could be used to estimate the chance of breast cancer returning or developing breast cancer in the first instance (a prognostic biomarker). In addition, changes in mammographic density might be able to predict how well a woman responds to endocrine therapy (a predictive biomarker). The role of breast density as a prognostic or predictive biomarker could help improve the management of breast cancer.

OBJECTIVES

To assess the evidence that a reduction in mammographic density following endocrine therapy for breast cancer prevention in women without previous breast cancer, or for treatment in women with early-stage hormone receptor-positive breast cancer, is a prognostic or predictive biomarker.

SEARCH METHODS

We searched the Cochrane Breast Cancer Group Specialised Register, CENTRAL, MEDLINE, Embase, and two trials registers on 3 August 2020 along with reference checking, bibliographic searching, and contact with study authors to obtain further data.

SELECTION CRITERIA

We included randomised, cohort and case-control studies of adult women with or without breast cancer receiving endocrine therapy. Endocrine therapy agents included were selective oestrogen receptor modulators and aromatase inhibitors. We required breast density before start of endocrine therapy and at follow-up. We included studies published in English.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently extracted data and assessed risk of bias using adapted Quality in Prognostic Studies (QUIPS) and Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tools. We used the GRADE approach to evaluate the certainty of the evidence. We did not perform a quantitative meta-analysis due to substantial heterogeneity across studies.

MAIN RESULTS

Eight studies met our inclusion criteria, of which seven provided data on outcomes listed in the protocol (5786 women). There was substantial heterogeneity across studies in design, sample size (349 to 1066 women), participant characteristics, follow-up (5 to 14 years), and endocrine therapy agent. There were five breast density measures and six density change definitions. All studies had at least one domain as at moderate or high risk of bias. Common concerns were whether the study sample reflected the review target population, and likely post hoc definitions of breast density change. Most studies on prognosis for women receiving endocrine therapy reported a reduced risk associated with breast density reduction. Across endpoints, settings, and agents, risk ratio point estimates (most likely value) were between 0.1 and 1.5, but with substantial uncertainty. There was greatest consistency in the direction and magnitude of the effect for tamoxifen (across endpoints and settings, risk ratio point estimates were between 0.3 and 0.7). The findings are summarised as follows. Prognostic biomarker findings: Treatment Breast cancer mortality Two studies of 823 women on tamoxifen (172 breast cancer deaths) reported risk ratio point estimates of ~0.4 and ~0.5 associated with a density reduction. The certainty of the evidence was low. Recurrence Two studies of 1956 women on tamoxifen reported risk ratio point estimates of ~0.4 and ~0.7 associated with a density reduction. There was risk of bias in methodology for design and analysis of the studies and considerable uncertainty over the size of the effect. One study of 175 women receiving an aromatase inhibitor reported a risk ratio point estimate of ~0.1 associated with a density reduction. There was considerable uncertainty about the effect size and a moderate or high risk of bias in all domains. One study of 284 women receiving exemestane or tamoxifen as part of a randomised controlled trial reported risk ratio point estimates of ~1.5 (loco-regional recurrence) and ~1.3 (distance recurrence) associated with a density reduction. There was risk of bias in reporting and study confounding, and uncertainty over the size of the effects. The certainty of the evidence for all recurrence endpoints was very low. Incidence of a secondary primary breast cancer Two studies of 451 women on exemestane, tamoxifen, or unknown endocrine therapy reported risk ratio point estimates of ~0.5 and ~0.6 associated with a density reduction. There was risk of bias in reporting and study confounding, and uncertainty over the effect size. The certainty of the evidence was very low. We were unable to find data regarding the remaining nine outcomes prespecified in the review protocol. Prevention Incidence of invasive breast cancer and ductal carcinoma in situ (DCIS) One study of 507 women without breast cancer who were receiving preventive tamoxifen as part of a randomised controlled trial (51 subsequent breast cancers) reported a risk ratio point estimate of ~0.3 associated with a density reduction. The certainty of the evidence was low. Predictive biomarker findings: One study of a subset of 1065 women from a randomised controlled trial assessed how much the effect of endocrine therapy could be explained by breast density declines in those receiving endocrine therapy. This study evaluated the prevention of invasive breast cancer and DCIS. We found some evidence to support the hypothesis, with a risk ratio interaction point estimate ~0.5. However, the 95% confidence interval included unity, and data were based on 51 women with subsequent breast cancer in the tamoxifen group. The certainty of the evidence was low.

AUTHORS' CONCLUSIONS

There is low-/very low-certainty evidence to support the hypothesis that breast density change following endocrine therapy is a prognostic biomarker for treatment or prevention. Studies suggested a potentially large effect size with tamoxifen, but the evidence was limited. There was less evidence that breast density change following tamoxifen preventive therapy is a predictive biomarker than prognostic biomarker. Evidence for breast density change as a prognostic treatment biomarker was stronger for tamoxifen than aromatase inhibitors. There were no studies reporting mammographic density change following endocrine therapy as a predictive biomarker in the treatment setting, nor aromatase inhibitor therapy as a prognostic or predictive biomarker in the preventive setting. Further research is warranted to assess mammographic density as a biomarker for all classes of endocrine therapy and review endpoints.

Prognostic factors of depression and depressive symptoms after hip fracture surgery: systematic review

Background

Patients with hip fracture and depression are less likely to recover functional ability. This review sought to identify prognostic factors of depression or depressive symptoms up to 1 year after hip fracture surgery in adults. This review also sought to describe proposed underlying mechanisms for their association with depression or depressive symptoms.

Methods

We searched for published (MEDLINE, Embase, PsychInfo, CINAHL and Web of Science Core Collection) and unpublished (OpenGrey, Greynet, BASE, conference proceedings) studies. We did not impose any date, geographical, or language limitations. Screening (Covidence), extraction (Checklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies, adapted for use with prognostic factors studies Checklist), and quality appraisal (Quality in Prognosis Studies tool) were completed in duplicate. Results were summarised narratively.

Results

In total, 37 prognostic factors were identified from 12 studies included in this review. The quality of the underlying evidence was poor, with all studies at high risk of bias in at least one domain. Most factors did not have a proposed mechanism for the association. Where factors were investigated by more than one study, the evidence was often conflicting.

Conclusion

Due to conflicting and low quality of available evidence it is not possible to make clinical recommendations based on factors prognostic of depression or depressive symptoms after hip fracture. Further high-quality research investigating prognostic factors is warranted to inform future intervention and/or stratified approaches to care after hip fracture.

Trial registration

Prospero registration: CRD42019138690.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02514-1.

Role of Digital Health and Artificial Intelligence in Inflammatory Bowel Disease: A Scoping Review

Inflammatory bowel diseases (IBD), subdivided into Crohn's disease (CD) and ulcerative colitis (UC), are chronic diseases that are characterized by relapsing and remitting periods of inflammation in the gastrointestinal tract. In recent years, the amount of research surrounding digital health (DH) and artificial intelligence (AI) has increased. The purpose of this scoping review is to explore this growing field of research to summarize the role of DH and AI in the diagnosis, treatment, monitoring and prognosis of IBD. A review of 21 articles revealed the impact of both AI algorithms and DH technologies; AI algorithms can improve diagnostic accuracy, assess disease activity, and predict treatment response based on data modalities such as endoscopic imaging and genetic data. In terms of DH, patients utilizing DH platforms experienced improvements in quality of life, disease literacy, treatment adherence, and medication management. In addition, DH methods can reduce the need for in-person appointments, decreasing the use of healthcare resources without compromising the standard of care. These articles demonstrate preliminary evidence of the potential of DH and AI for improving the management of IBD. However, the majority of these studies were performed in a regulated clinical environment. Therefore, further validation of these results in a real-world environment is required to assess the efficacy of these methods in the general IBD population.

Factors Associated with Successful Video-Assisted Thoracoscopic Surgery and Thoracotomy in the Management of Traumatic Hemothorax

BACKGROUND

Few studies have identified factors associated with successful VATS or thoracotomy as the initial operative strategy among patients with traumatic hemothorax.

MATERIAL AND METHODS

We performed an exploratory analysis using the 2008 to 2017 TQP database. We identified all patients aged 18 to 89 years with traumatic hemothorax who were treated with tube thoracostomy alone in the first 24-hours of admission, followed by VATS or thoracotomy. Logistic regression was used to identify factors associated with successful VATS (no conversion or reoperation) or thoracotomy (no reoperation) as the initial operative strategy.

RESULTS

Among 2052 patients managed with initial VATS after chest tube drainage, 1710 (83%) were successful, while 263 (13%) were converted to thoracotomy and 79 (4%) required reoperation. On multivariable analysis, poor GCS (OR = 0.96 [95% CI = 0.94-0.99]), major injury (OR = 0.69 [95% CI = 0.53-0.90]), and diaphragmatic injury (OR = 0.42 [95% CI = 0.30-0.60]) were associated with lower odds of successful VATS, while rib fractures (OR=1.29 [95% CI=1.01-1.66]) were associated with higher odds of success of the initial operative plan. Among 3486 patients initially managed with thoracotomy after drainage with tube thoracostomy, 3118 (89.4%) were successful, while 11% (n = 368) required reoperation. Multivariable analysis revealed that major injury (OR = 0.68 [95% CI = 0.50-0.92]), blunt mechanism (OR = 0.63 [95% CI = 0.50-0.78]), and diaphragmatic injury (OR = 0.67, 95% CI = 0.53-0.84]) were associated with lower odds of successful thoracotomy as the initial operative plan.

CONCLUSIONS

More severe injuries and diaphragmatic injuries have lower odds of successful of VATS or thoracotomy as the initial operative management strategy among patients with traumatic hemothorax. Rib fractures may be associated with higher odds of success of VATS as the initial management strategy.

Doug Altman: Driving critical appraisal and improvements in the quality of methodological and medical research

Doug Altman was a visionary leader and one of the most influential medical statisticians of the last 40 years. Based on a presentation in the "Invited session in memory of Doug Altman" at the 40th Annual Conference of the International Society for Clinical Biostatistics (ISCB) in Leuven, Belgium and our long-standing collaborations with Doug, we discuss his contributions to regression modeling, reporting, prognosis research, as well as some more general issues while acknowledging that we cannot cover the whole spectrum of Doug's considerable methodological output. His statement "To maximize the benefit to society, you need to not just do research but do it well" should be a driver for all researchers. To improve current and future research, we aim to summarize Doug's messages for these three topics.

Defining Clinical Utility of Tumor Biomarker Tests: A Clinician's Viewpoint

Tumor biomarker tests (TBTs) are used to guide therapeutic strategies for patients with cancer. However, the regulatory environment for TBTs in the United States is inconsistent and, in general, TBTs are poorly valued. The National Academy of Medicine has recommended that TBTs should not be used in general practice until they are shown to have analytical validity and clinical utility. The latter term, first coined by the Evaluation of Genomic Applications in Practice and Prevention Initiative, has been widely stated but is indeterminately defined. In considering whether a TBT has clinical utility, several factors need to be considered: (1) What is the intended use of the TBT? (2) What are the end points that are used to determine clinical utility? (3) How substantial does the difference in end points between groups defined by the TBT need to be to determine therapeutic strategies? (4) What is the risk tolerance of the stakeholders? and (5) Who are the stakeholders that make the decision? For all these factors, the data used to consider clinical utility must be derived from level I evidence studies. In conclusion, there is no strict definition of clinical utility for a TBT. However, consideration of these factors will lead to more objective conclusions. Doing so will facilitate value-based decisions regarding whether a TBT should be used to guide patient care.

Factors associated with outcome following exercise interventions for Achilles tendinopathy: A systematic review

OBJECTIVE

This systematic review aimed to synthesize current evidence on contributing factors influencing outcome following exercise management for Achilles tendinopathy (AT).

DATA SOURCES

Databases (PubMed, Embase, and Cochrane Library) were searched from inception to February 2020.

STUDY SELECTION

Studies investigating factors (e.g., age, BMI) associated with outcome (e.g., pain and function questionnaires) following exercise interventions for AT were included.

DATA EXTRACTION

Data were extracted into a standardized form, including patient demographics, population sample, study type, factors associated with outcome, and outcome measures.

DATA SYNTHESIS

Meta-analysis was planned to be performed, where appropriate. Where data could not be pooled, we summarized the findings descriptively.

RESULTS

Six studies investigating 11 different factors were included; overall the quality of evidence was poor. There was conflicting evidence that imaging measures had an association with a change in VISA-A outcome. These included signal intensity and tendon size determined by MRI, and Ultrasound Tissue Characterization echopattern. Three studies found that duration of symptoms was not associated with a change in VISA-A. Also, three studies found that age, and one study found that prior sporting activity level, were not associated with outcome. Baseline pain with activity, baseline VISA-A, sex, and BMI were inconsistently associated with specific outcomes.

CONCLUSION

Due to the poor quality of evidence overall, no firm conclusions can be drawn. At best, there was inconsistent evidence that imaging factors, baseline pain and function, BMI, and sex showed some associations with outcomes, but these findings need to be confirmed in more extensive studies.

Nothing wrong about change: the adequate choice of the dependent variable and design in prediction of cognitive training success

Background

Even though investigating predictors of intervention success (e.g Cognitive Training, CT) is gaining more and more interest in the light of an individualized medicine, results on specific predictors of intervention success in the overall field are mixed and inconsistent due to different and sometimes inappropriate statistical methods used. Therefore, the present paper gives a guidance on the appropriate use of multiple regression analyses to identify predictors of CT and similar non-pharmacological interventions.

Methods

We simulated data based on a predefined true model and ran a series of different analyses to evaluate their performance in retrieving the true model coefficients. The true model consisted of a 2 (between: experimental vs. control group) × 2 (within: pre- vs. post-treatment) design with two continuous predictors, one of which predicted the success in the intervention group and the other did not. In analyzing the data, we considered four commonly used dependent variables (post-test score, absolute change score, relative change score, residual score), five regression models, eight sample sizes, and four levels of reliability.

Results

Our results indicated that a regression model including the investigated predictor, Group (experimental vs. control), pre-test score, and the interaction between the investigated predictor and the Group as predictors, and the absolute change score as the dependent variable seemed most convenient for the given experimental design. Although the pre-test score should be included as a predictor in the regression model for reasons of statistical power, its coefficient should not be interpreted because even if there is no true relationship, a negative and statistically significant regression coefficient commonly emerges.

Conclusion

Employing simulation methods, theoretical reasoning, and mathematical derivations, we were able to derive recommendations regarding the analysis of data in one of the most prevalent experimental designs in research on CT and external predictors of CT success. These insights can contribute to the application of considered data analyses in future studies and facilitate cumulative knowledge gain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-020-01176-8.

Functional Recovery after Surgery for Lumbar Spinal Stenosis in Patients with Hypertension

Hypertension is a prevalent condition that is associated with lower health status in patients with lumbar spinal stenosis. The study determined whether hypertension is a prognostic factor associated with functional recovery after spine surgery for lumbar spinal stenosis. This was a secondary analysis of the Alberta Lumbar Spinal Stenosis Study in which patients were identified as participants at the time of lumbosacral magnetic resonance imaging or computed tomography in Calgary, Alberta, Canada. Multivariable linear regression analyses were performed to examine hypertension as a prognostic factor of functional recovery after surgery (Oswestry Disability Index, the Swiss Spinal Stenosis (SSS)-Symptom Severity and SSS-Physical Function scales). Of the 97 surgical participants, 49 who were hypertensive were older (76.8, SD 11.4 years) than the 48 non-hypertensive participants (66.7, SD 12.4 years) (p < 0.001). No significant associations between hypertension and post-operative function in any of the three multivariable models were seen. The Oswestry Disability Index mean score improved after surgery (effect size: 1.73; 95%CI: 1.39, 2.06), with no differences seen between those with and without hypertension (p = 0.699). Large changes were seen after surgery for the SSS-Symptom Severity (effect size: 1.0, 95%CI 0.7, 1.3) and SSS-Physical Function (effect size: 0.9, 95%CI 0.6, 1.2) scales. Hypertension alone does not negatively impact functional recovery following surgery.

Risk factors for the progression of finger interphalangeal joint osteoarthritis: a systematic review

Progressive hand interphalangeal joint (IPJ) osteoarthritis is associated with pain, reduced function and impaired quality of life. However, the evidence surrounding risk factors for IPJ osteoarthritis progression is unclear. Identifying risk factors for IPJ osteoarthritis progression may inform preventative strategies and early interventions to improve long-term outcomes for individuals at risk of IPJ osteoarthritis progression. The objectives of the study were to describe methods used to measure the progression of IPJ osteoarthritis and identify risk factors for IPJ osteoarthritis progression. MEDLINE, EMBASE, Scopus, and The Cochrane Library were searched from inception to 19th February 2020 (PROSPERO CRD42019121034). Eligible studies assessed potential risk factor/s associated with IPJ osteoarthritis progression. Risk of bias was assessed using a modified QUIPS Tool, and a best evidence synthesis was performed. Of eight eligible studies, all measured osteoarthritis progression radiographically, and none considered symptoms. Eighteen potential risk factors were assessed. Diabetes (adjusted mean difference between 2.06 and 7.78), and larger finger epiphyseal index in males (regression coefficient β = 0.202) and females (β = 0.325) were identified as risk factors (limited evidence). Older age in men and women showed mixed results; 13 variables were not risk factors (all limited evidence). Patients with diabetes and larger finger epiphyseal index might be at higher risk of radiographic IPJ osteoarthritis progression, though evidence is limited and studies are biased. Studies assessing symptomatic IPJ osteoarthritis progression are lacking.

Systematic review and REMARK scoring of renal cell carcinoma prognostic circulating biomarker manuscripts

Background

No validated molecular biomarkers exist to help guide prognosis of renal cell carcinoma (RCC) patients. We seek to evaluate the quality of published prognostic circulating RCC biomarker manuscripts using the Reporting Recommendations for Tumor Marker Prognostic Studies (REMARK) guidelines.

Methods

The phrase “(renal cell carcinoma OR renal cancer OR kidney cancer OR kidney carcinoma) AND circulating AND (biomarkers OR cell free DNA OR tumor DNA OR methylated cell free DNA OR methylated tumor DNA)” was searched in Embase, Medline and PubMed March 2018. Relevant manuscripts were scored using 48 REMARK sub-criteria for a maximal score of 20 points.

Results

The search identified 535 publications: 33 were manuscripts of primary research and were analyzed. The mean REMARK score was 10.6 (range 6.42–14.2). All manuscripts stated their biomarker, study objectives and method of case selection. The lowest scoring criteria: time lapse between storage of blood/serum and marker assay (n = 2) and lack of flow diagram (n = 2). REMARK scores were significantly higher in publications stating adherence to REMARK guidelines (p = 0.0307) and reporting statistically significant results (p = 0.0318).

Conclusions

Most RCC prognostic biomarker manuscripts poorly adhere to the REMARK guidelines. Better designed studies and appropriate reporting are required to address this urgent unmet need.

A systematic review of methodological quality of model development studies predicting prognostic outcome for resectable pancreatic cancer

OBJECTIVES

To assess the methodological quality of prognostic model development studies pertaining to post resection prognosis of pancreatic ductal adenocarcinoma (PDAC).

DESIGN/SETTING

A narrative systematic review of international peer reviewed journals DATA SOURCE: Searches were conducted of: MEDLINE, Embase, PubMed, Cochrane database and Google Scholar for predictive modelling studies applied to the outcome of prognosis for patients with PDAC post resection. Predictive modelling studies in this context included prediction model development studies with and without external validation and external validation studies with model updating. Data was extracted following the Checklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies (CHARMS) checklist.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes were all components of the CHARMS checklist. Secondary outcomes included frequency of variables included across predictive models.

RESULTS

263 studies underwent full text review. 15 studies met the inclusion criteria. 3 studies underwent external validation. Multivariable Cox proportional hazard regression was the most commonly employed modelling method (n=13). 10 studies were based on single centre databases. Five used prospective databases, seven used retrospective databases and three used cancer data registry. The mean number of candidate predictors was 19.47 (range 7 to 50). The most commonly included variables were tumour grade (n=9), age (n=8), tumour stage (n=7) and tumour size (n=5). Mean sample size was 1367 (range 50 to 6400). 5 studies reached statistical power. None of the studies reported blinding of outcome measurement for predictor values. The most common form of presentation was nomograms (n=5) and prognostic scores (n=5) followed by prognostic calculators (n=3) and prognostic index (n=2).

CONCLUSIONS

Areas for improvement in future predictive model development have been highlighted relating to: general aspects of model development and reporting, applicability of models and sources of bias.

TRIAL REGISTRATION NUMBER

CRD42018105942.

Using microRNAs as Novel Predictors of Urologic Cancer Survival: An Integrated Analysis

BACKGROUND

MicroRNAs(miRNAs) are involved in the formation, maintenance, and metastasis of urologic cancer. Here, we aim to gather and evaluate all of the evidence regarding the potential role of miRNAs as novel predictors of urologic cancer survival.

METHODS

A systematic review was performed to identify and score all of the published studies that evaluated the prognostic effects of miRNAs in kidney (KCa), bladder (BCa) or prostate cancer (PCa). Where appropriate, the summary effects of miRNAs on urologic cancer were meta-analysed. The reliability of those results was then further validated by an integrated analysis of the TCGA cohort and miRNA panel.

RESULTS

Of 151 datasets, 80 miRNAs were enrolled in this systematic review. A meta-analysis of the prognostic qualities of each miRNA identified an objective association between miRNA and prognosis. miR-21 was identified as an unfavourable miRNA with the overall survival (HR:2.699, 1.76-4.14, P < 0.001) across various prognostic events. Our further meta-analyses, integrating a parallel TCGA analysis, confirmed these partial previous results and further revealed different summary effects, such as the moderate effect of miR-21 in BCa. The refined miRNA panel (KCa-6: miR-27b, -942, -497, -144, -141 and -27a) was more capable of predicting the overall survival than was any single miRNAs included in it (HR: 3.214, 1.971-5.240, P < 0.01).

CONCLUSIONS

A miRNA panel may be able to determine the prognosis of urologic tumour more effectively and compensate for the unreliability of individual miRNA in estimating prognosis. More large-scale studies are therefore required to evaluate the unbiased prognostic value of miRNAs in urologic cancer effectively.

Did the reporting of prognostic studies of tumour markers improve since the introduction of REMARK guideline? A comparison of reporting in published articles

Although biomarkers are perceived as highly relevant for future clinical practice, few biomarkers reach clinical utility for several reasons. Among them, poor reporting of studies is one of the major problems. To aid improvement, reporting guidelines like REMARK for tumour marker prognostic (TMP) studies were introduced several years ago. The aims of this project were to assess whether reporting quality of TMP-studies improved in comparison to a previously conducted study assessing reporting quality of TMP-studies (PRE-study) and to assess whether articles citing REMARK (citing group) are better reported, in comparison to articles not citing REMARK (not-citing group). For the POST-study, recent articles citing and not citing REMARK (53 each) were identified in selected journals through systematic literature search and evaluated in same way as in the PRE-study. Ten of the 20 items of the REMARK checklist were evaluated and used to define an overall score of reporting quality. The observed overall scores were 53.4% (range: 10%-90%) for the PRE-study, 57.7% (range: 20%-100%) for the not-citing group and 58.1% (range: 30%-100%) for the citing group of the POST-study. While there is no difference between the two groups of the POST-study, the POST-study shows a slight but not relevant improvement in reporting relative to the PRE-study. Not all the articles of the citing group, cited REMARK appropriately. Irrespective of whether REMARK was cited, the overall score was slightly higher for articles published in journals requesting adherence to REMARK than for those published in journals not requesting it: 59.9% versus 51.9%, respectively. Several years after the introduction of REMARK, many key items of TMP-studies are still very poorly reported. A combined effort is needed from authors, editors, reviewers and methodologists to improve the current situation. Good reporting is not just nice to have but is essential for any research to be useful.

Vitamin and mineral status in chronic fatigue syndrome and fibromyalgia syndrome: A systematic review and meta-analysis

BACKGROUND

Many chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FMS) patients (35-68%) use nutritional supplements, while it is unclear whether deficiencies in vitamins and minerals contribute to symptoms in these patients. Objectives were (1) to determine vitamin and mineral status in CFS and FMS patients as compared to healthy controls; (2) to investigate the association between vitamin and mineral status and clinical parameters, including symptom severity and quality of life; and (3) to determine the effect of supplementation on clinical parameters.

METHODS

The databases PubMed, EMBASE, Web of Knowledge, and PsycINFO were searched for eligible studies. Articles published from January 1st 1994 for CFS patients and 1990 for FMS patients till March 1st 2017 were included. Articles were included if the status of one or more vitamins or minerals were reported, or an intervention concerning vitamins or minerals was performed. Two reviewers independently extracted data and assessed the risk of bias.

RESULTS

A total of 5 RCTs and 40 observational studies were included in the qualitative synthesis, of which 27 studies were included in the meta-analyses. Circulating concentrations of vitamin E were lower in patients compared to controls (pooled standardized mean difference (SMD): -1.57, 95%CI: -3.09, -0.05; p = .042). However, this difference was not present when restricting the analyses to the subgroup of studies with high quality scores. Poor study quality and a substantial heterogeneity in most studies was found. No vitamins or minerals have been repeatedly or consistently linked to clinical parameters. In addition, RCTs testing supplements containing these vitamins and/or minerals did not result in clinical improvements.

DISCUSSION

Little evidence was found to support the hypothesis that vitamin and mineral deficiencies play a role in the pathophysiology of CFS and FMS, and that the use of supplements is effective in these patients.

REGISTRATION

Study methods were documented in an international prospective register of systematic reviews (PROSPERO) protocol, registration number: http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015032528.

Predictive value of initial FDG-PET features for treatment response and survival in esophageal cancer patients treated with chemo-radiation therapy using a random forest classifier

Purpose

In oncology, texture features extracted from positron emission tomography with 18-fluorodeoxyglucose images (FDG-PET) are of increasing interest for predictive and prognostic studies, leading to several tens of features per tumor. To select the best features, the use of a random forest (RF) classifier was investigated.

Methods

Sixty-five patients with an esophageal cancer treated with a combined chemo-radiation therapy were retrospectively included. All patients underwent a pretreatment whole-body FDG-PET. The patients were followed for 3 years after the end of the treatment. The response assessment was performed 1 month after the end of the therapy. Patients were classified as complete responders and non-complete responders. Sixty-one features were extracted from medical records and PET images. First, Spearman’s analysis was performed to eliminate correlated features. Then, the best predictive and prognostic subsets of features were selected using a RF algorithm. These results were compared to those obtained by a Mann-Whitney U test (predictive study) and a univariate Kaplan-Meier analysis (prognostic study).

Results

Among the 61 initial features, 28 were not correlated. From these 28 features, the best subset of complementary features found using the RF classifier to predict response was composed of 2 features: metabolic tumor volume (MTV) and homogeneity from the co-occurrence matrix. The corresponding predictive value (AUC = 0.836 ± 0.105, Se = 82 ± 9%, Sp = 91 ± 12%) was higher than the best predictive results found using the Mann-Whitney test: busyness from the gray level difference matrix (P < 0.0001, AUC = 0.810, Se = 66%, Sp = 88%). The best prognostic subset found using RF was composed of 3 features: MTV and 2 clinical features (WHO status and nutritional risk index) (AUC = 0.822 ± 0.059, Se = 79 ± 9%, Sp = 95 ± 6%), while no feature was significantly prognostic according to the Kaplan-Meier analysis.

Conclusions

The RF classifier can improve predictive and prognostic values compared to the Mann-Whitney U test and the univariate Kaplan-Meier survival analysis when applied to several tens of features in a limited patient database.

Challenges and methodology in the incorporation of biomarkers in cancer clinical trials

Biomarkers can be used to establish more homogeneous groups using the genetic makeup of the tumour to inform the selection of treatment for each individual patient. However, proper preclinical work and stringent validation are needed before taking forward biomarkers into confirmatory studies. Despite the challenges, incorporation of biomarkers into clinical trials could better target appropriate patients, and potentially be lifesaving. The authors conducted a systematic review to describe marker-based and adaptive design methodology for their integration in clinical trials, and to further describe the associated practical challenges. Studies published between 1990 to November 2015 were searched on PubMed. Titles, abstracts and full text articles were reviewed to identify relevant studies. Of the 4438 studies examined, 57 studies were included. The authors conclude that the proposed approaches may readily help researchers to design biomarker trials, but novel approaches are still needed.

A systematic review and individual patient data meta-analysis of prognostic factors for foot ulceration in people with diabetes: the international research collaboration for the prediction of diabetic foot ulcerations (PODUS)

BACKGROUND

Annual foot risk assessment of people with diabetes is recommended in national and international clinical guidelines. At present, these are consensus based and use only a proportion of the available evidence.

OBJECTIVES

We undertook a systematic review of individual patient data (IPD) to identify the most highly prognostic factors for foot ulceration (i.e. symptoms, signs, diagnostic tests) in people with diabetes.

DATA SOURCES

Studies were identified from searches of MEDLINE and EMBASE.

REVIEW METHODS

The electronic search strategies for MEDLINE and EMBASE databases created during an aggregate systematic review of predictive factors for foot ulceration in diabetes were updated and rerun to January 2013. One reviewer applied the IPD review eligibility criteria to the full-text articles of the studies identified in our literature search and also to all studies excluded from our aggregate systematic review to ensure that we did not miss eligible IPD. A second reviewer applied the eligibility criteria to a 10% random sample of the abstract search yield to check that no relevant material was missed. This review includes exposure variables (risk factors) only from individuals who were free of foot ulceration at the time of study entry and who had a diagnosis of diabetes mellitus (either type 1 or type 2). The outcome variable was incident ulceration.

RESULTS

Our search identified 16 cohort studies and we obtained anonymised IPD for 10. These data were collected from more than 16,000 people with diabetes worldwide and reanalysed by us. One data set was kept for independent validation. The data sets contributing IPD covered a range of temporal, geographical and clinical settings. We therefore selected random-effects meta-analysis, which assumes not that all the estimates from each study are estimates of the same underlying true value, but rather that the estimates belong to the same distribution. We selected candidate variables for meta-analysis using specific criteria. After univariate meta-analyses, the most clinically important predictors were identified by an international steering committee for inclusion in the primary, multivariable meta-analysis. Age, sex, duration of diabetes, monofilaments and pulses were considered most prognostically important. Meta-analyses based on data from the entire IPD population found that an inability to feel a 10-g monofilament [odds ratio (OR) 3.184, 95% confidence interval (CI) 2.654 to 3.82], at least one absent pedal pulse (OR 1.968, 95% CI 1.624 to 2.386), a longer duration of a diagnosis of diabetes (OR 1.024, 95% CI 1.011 to 1.036) and a previous history of ulceration (OR 6.589, 95% CI 2.488 to 17.45) were all predictive of risk. Female sex was protective (OR 0.743, 95% CI 0.598 to 0.922).

LIMITATIONS

It was not possible to perform a meta-analysis using a one-step approach because we were unable to procure copies of one of the data sets and instead accessed data via Safe Haven.

CONCLUSIONS

The findings from this review identify risk assessment procedures that can reliably inform national and international diabetes clinical guideline foot risk assessment procedures. The evidence from a large sample of patients in worldwide settings show that the use of a 10-g monofilament or one absent pedal pulse will identify those at moderate or intermediate risk of foot ulceration, and a history of foot ulcers or lower-extremity amputation is sufficient to identify those at high risk. We propose the development of a clinical prediction rule (CPR) from our existing model using the following predictor variables: insensitivity to a 10-g monofilament, absent pedal pulses and a history of ulceration or lower-extremities amputations. This CPR could replace the many tests, signs and symptoms that patients currently have measured using equipment that is either costly or difficult to use.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42011001841.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The prognostic utility of tests of platelet function for the detection of 'aspirin resistance' in patients with established cardiovascular or cerebrovascular disease: a systematic review and economic evaluation

BACKGROUND

The use of aspirin is well established for secondary prevention of cardiovascular disease. However, a proportion of patients suffer repeat cardiovascular events despite being prescribed aspirin treatment. It is uncertain whether or not this is due to an inherent inability of aspirin to sufficiently modify platelet activity. This report aims to investigate whether or not insufficient platelet function inhibition by aspirin ('aspirin resistance'), as defined using platelet function tests (PFTs), is linked to the occurrence of adverse clinical outcomes, and further, whether or not patients at risk of future adverse clinical events can be identified through PFTs.

OBJECTIVES

To review systematically the clinical effectiveness and cost-effectiveness evidence regarding the association between PFT designation of 'aspirin resistance' and the risk of adverse clinical outcome(s) in patients prescribed aspirin therapy. To undertake exploratory model-based cost-effectiveness analysis on the use of PFTs.

DATA SOURCES

Bibliographic databases (e.g. MEDLINE from inception and EMBASE from 1980), conference proceedings and ongoing trial registries up to April 2012.

METHODS

Standard systematic review methods were used for identifying clinical and cost studies. A risk-of-bias assessment tool was adapted from checklists for prognostic and diagnostic studies. (Un)adjusted odds and hazard ratios for the association between 'aspirin resistance', for different PFTs, and clinical outcomes are presented; however, heterogeneity between studies precluded pooling of results. A speculative economic model of a PFT and change of therapy strategy was developed.

RESULTS

One hundred and eight relevant studies using a variety of PFTs, 58 in patients on aspirin monotherapy, were analysed in detail. Results indicated that some PFTs may have some prognostic utility, i.e. a trend for more clinical events to be associated with groups classified as 'aspirin resistant'. Methodological and clinical heterogeneity prevented a quantitative summary of prognostic effect. Study-level effect sizes were generally small and absolute outcome risk was not substantially different between 'aspirin resistant' and 'aspirin sensitive' designations. No studies on the cost-effectiveness of PFTs for 'aspirin resistance' were identified. Based on assumptions of PFTs being able to accurately identify patients at high risk of clinical events and such patients benefiting from treatment modification, the economic model found that a test-treat strategy was likely to be cost-effective. However, neither assumption is currently evidence based.

LIMITATIONS

Poor or incomplete reporting of studies suggests a potentially large volume of inaccessible data. Analyses were confined to studies on patients prescribed aspirin as sole antiplatelet therapy at the time of PFT. Clinical and methodological heterogeneity across studies precluded meta-analysis. Given the lack of robust data the economic modelling was speculative.

CONCLUSIONS

Although evidence indicates that some PFTs may have some prognostic value, methodological and clinical heterogeneity between studies and different approaches to analyses create confusion and inconsistency in prognostic results, and prevented a quantitative summary of their prognostic effect. Protocol-driven and adequately powered primary studies are needed, using standardised methods of measurements to evaluate the prognostic ability of each test in the same population(s), and ideally presenting individual patient data. For any PFT to inform individual risk prediction, it will likely need to be considered in combination with other prognostic factors, within a prognostic model.

STUDY REGISTRATION

This study is registered as PROSPERO 2012:CRD42012002151.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Discrimination-based sample size calculations for multivariable prognostic models for time-to-event data

Background

Prognostic studies of time-to-event data, where researchers aim to develop or validate multivariable prognostic models in order to predict survival, are commonly seen in the medical literature; however, most are performed retrospectively and few consider sample size prior to analysis. Events per variable rules are sometimes cited, but these are based on bias and coverage of confidence intervals for model terms, which are not of primary interest when developing a model to predict outcome. In this paper we aim to develop sample size recommendations for multivariable models of time-to-event data, based on their prognostic ability.

Methods

We derive formulae for determining the sample size required for multivariable prognostic models in time-to-event data, based on a measure of discrimination, D, developed by Royston and Sauerbrei. These formulae fall into two categories: either based on the significance of the value of D in a new study compared to a previous estimate, or based on the precision of the estimate of D in a new study in terms of confidence interval width. Using simulation we show that they give the desired power and type I error and are not affected by random censoring. Additionally, we conduct a literature review to collate published values of D in different disease areas.

Results

We illustrate our methods using parameters from a published prognostic study in liver cancer. The resulting sample sizes can be large, and we suggest controlling study size by expressing the desired accuracy in the new study as a relative value as well as an absolute value. To improve usability we use the values of D obtained from the literature review to develop an equation to approximately convert the commonly reported Harrell’s c-index to D. A flow chart is provided to aid decision making when using these methods.

Conclusion

We have developed a suite of sample size calculations based on the prognostic ability of a survival model, rather than the magnitude or significance of model coefficients. We have taken care to develop the practical utility of the calculations and give recommendations for their use in contemporary clinical research.

A new approach to categorising continuous variables in prediction models: Proposal and validation

When developing prediction models for application in clinical practice, health practitioners usually categorise clinical variables that are continuous in nature. Although categorisation is not regarded as advisable from a statistical point of view, due to loss of information and power, it is a common practice in medical research. Consequently, providing researchers with a useful and valid categorisation method could be a relevant issue when developing prediction models. Without recommending categorisation of continuous predictors, our aim is to propose a valid way to do it whenever it is considered necessary by clinical researchers. This paper focuses on categorising a continuous predictor within a logistic regression model, in such a way that the best discriminative ability is obtained in terms of the highest area under the receiver operating characteristic curve (AUC). The proposed methodology is validated when the optimal cut points’ location is known in theory or in practice. In addition, the proposed method is applied to a real data-set of patients with an exacerbation of chronic obstructive pulmonary disease, in the context of the IRYSS-COPD study where a clinical prediction rule for severe evolution was being developed. The clinical variable PCO2 was categorised in a univariable and a multivariable setting.

Critical appraisal and data extraction for systematic reviews of prediction modelling studies: the CHARMS checklist

Carl Moons and colleagues provide a checklist and background explanation for critically appraising and extracting data from systematic reviews of prognostic and diagnostic prediction modelling studies. Please see later in the article for the Editors' Summary.

The course and prognostic factors of symptomatic cervical disc herniation with radiculopathy: a systematic review of the literature

BACKGROUND CONTEXT

Cervical spine disc herniation is a disabling source of cervical radiculopathy. However, little is known about its course and prognosis. Understanding the course and prognosis of symptomatic cervical disc herniation is necessary to guide patients' expectations and assist clinicians in managing patients.

PURPOSE

To describe the natural history, clinical course, and prognostic factors of symptomatic cervical disc herniations with radiculopathy.

STUDY DESIGN

Systematic review of the literature and best evidence synthesis.

METHODS

A systematic search of MEDLINE, EMBASE, CINAHL, SportsDiscus, and the Cochrane Central Register of Controlled Trials from inception to 2013 was conducted to retrieve eligible articles. Eligible articles were critically appraised using the Scottish Intercollegiate Guidelines Network criteria. The results from articles with low risk of bias were analyzed using best evidence synthesis principles.

RESULTS

We identified 1,221 articles. Of those, eight articles were eligible and three were accepted as having a low risk of bias. Two studies pertained to course and one study pertained to prognosis. Most patients with symptomatic cervical disc herniations with radiculopathy initially present with intense pain and moderate levels of disability. However, substantial improvements tend to occur within the first 4 to 6 months post-onset. Time to complete recovery ranged from 24 to 36 months in, approximately, 83% of patients. Patients with a workers' compensation claim appeared to have a poorer prognosis.

CONCLUSIONS

Our best evidence synthesis describes the best available evidence on the course and prognosis of cervical disc herniations with radiculopathy. Most patients with symptomatic cervical spine disc herniation with radiculopathy recover. Possible recurrences and time to complete recovery need to be further studied. More studies are also needed to understand the prognostic factors for this condition.

Prognostic factors for morbidity and mortality in elderly patients undergoing acute gastrointestinal surgery: a systematic review

BACKGROUND

Elderly patients undergoing acute gastrointestinal (GI) surgery experience increased morbidity and mortality compared with younger and elective patients. Prognostic factors can be used to counsel patients of these risks and, if modifiable, to minimize them. We reviewed the literature on prognostic factors for adverse outcomes in elderly patients undergoing acute GI surgery.

METHODS

We searched PubMed and Embase using a strategy developed in collaboration with an expert librarian. Studies examining independent associations between prognostic factors and morbidity or mortality in patients aged 65 and older undergoing acute GI surgery were selected. We extracted data using a standardized form and assessed study quality using the QUIPS tool.

RESULTS

Nine cohort studies representing 2958 patients satisfied our selection criteria. All studies focused on postoperative mortality. Thirty-four prognostic factors were examined, with significant variability across studies. There was limited or conflicting evidence for most prognostic factors. Meta-analysis was only possible for the American Society of Anesthesiologists (ASA) score, which was found to be associated with mortality in 4 studies (pooled odds ratio 2.77, 95% confidence interval 0.92-8.41).

CONCLUSION

While acute GI surgery in elderly patients is becoming increasingly common, the literature on prognostic factors for morbidity and mortality in this patient population lags behind. Further research is needed to help guide patient care and potentially improve outcomes.

Self-reported moderate-to-vigorous leisure time physical activity predicts less pain and disability over 12 months in chronic and persistent low back pain

BACKGROUND

Physical deconditioning in combination with societal and emotional factors has been hypothesized to compromise complete recovery from low back pain (LBP). However, there is a lack of longitudinal studies designed to specifically investigate physical activity as an independent prognostic factor. We conducted a prognostic study to investigate whether levels of leisure time physical activity are independently associated with clinical outcomes in people seeking care for chronic and persistent LBP.

METHODS

A total of 815 consecutive patients presenting with LBP to an outpatient spine centre in secondary care were recruited. Separate multivariate linear regression analyses were performed to investigate whether levels of leisure time physical activity (i.e., sedentary, light and moderate-to-vigorous leisure time physical activity levels) predict pain and disability at 12-month follow-up, after adjusting for age, pain, episode duration, disability, neurological symptoms, depression and fear of movement.

RESULTS

Final models showed evidence of an association between baseline physical activity and 12-month outcomes (p < 0.001). In both models, the moderate-to-vigorous physical activity group reported less pain and disability compared with the sedentary group.

CONCLUSIONS

Our findings suggest that physical activity levels may have a role in the prognosis of LBP. Specific domains of physical activity warrant further investigation to better understand this association.

Early predictors of remission in newly diagnosed epilepsy: a systematic approach to reviewing prognostic factor studies

BACKGROUND

It is necessary to select a range of consistently identified prognostic factors from exploratory studies to include in multivariate models of confirmatory studies. We illustrate a systematic approach to selecting consistently identified prognostic factors using the example of predictors of remission in newly diagnosed epilepsy.

METHODS

Medline and Embase were searched for reports of cohort studies enrolling at least 100 people with epilepsy within 1 year of diagnosis, and followed up for at least 1 year. We included studies that identified predictors of remission after adjusting for confounders using multivariate regression analysis. To identify consistent predictors a chart was designed to list the variables considered for inclusion in each model and those retained in more than one model from different cohorts were deemed to be consistent.

RESULTS

Remission off medication was less likely if there was more than one seizure between 6 and 12 months on medication and if there was comorbid intellectual disability in childhood onset epilepsy. The likelihood of remission on or off medication reduces with mixed seizure types at onset, intellectual disability, symptomatic aetiology, and also with increasing number of seizures before diagnosis or in the first 6 months after diagnosis.

CONCLUSION

A greater number of seizures before diagnosis and early in treatment, intellectual disability, and symptomatic aetiology are consistent predictors of less likelihood of remission. This suggests that early identification, diagnosis of epilepsy, and seizure control should be the primary aim of medical intervention, and that these predictors should be included in future confirmatory studies of prognostic factors of remission in newly diagnosed epilepsy.

Low bone density in systemic sclerosis. A systematic review

OBJECTIVE

The effect of systemic sclerosis (SSc) on bone density is not well understood. Through systematic review of the literature, the objectives of this study were to synthesize data about the prevalence of low bone mineral density (BMD), risk factors for low BMD, and occurrence of fracture and fracture-related mortality in SSc.

METHODS

A search was conducted of MEDLINE (1948-2012), Evidence Based Medicine Reviews (1991-2012), EMBASE (1980-2012), and CINAHL (1981-2012). Abstracts were screened to identify studies that evaluated low BMD in patients with SSc. Two investigators independently used a standardized form to abstract prevalence of osteopenia and osteoporosis (OP); risk factors for low BMD, BMD measurements, frequency of fracture, and fracture-related mortality.

RESULTS

Screening of 1032 citations identified 19 articles. Fifteen studies compared patients with SSc to controls. Most patients were white, female (prevalence 74%-100%), and postmenopausal (prevalence 45.9%-100%). The prevalence of low BMD and OP was 27%-53.3% and 3%-51.1%, respectively. Ten studies reported a lower BMD in patients with SSc compared to matched controls, whereas 2 studies reported no difference. Candidate risk factors for low BMD in SSc include family history of OP, age, menopause, diffuse subtype, presence of internal organ involvement, low vitamin D levels, and calcinosis. However, the studies supporting these factors were conflicting. Fracture rate ranged between 0% and 38%. No study reported OP-related fracture mortality.

CONCLUSION

The data suggest that patients with SSc are at risk of low BMD and fracture, especially when other risk factors for OP are present. The interaction of SSc manifestations, traditional OP risk factors, and clinically relevant outcomes is complex and warrants further research.

Judging the quality of evidence in reviews of prognostic factor research: adapting the GRADE framework

BACKGROUND

Prognosis research aims to identify factors associated with the course of health conditions. It is often challenging to judge the overall quality of research evidence in systematic reviews about prognosis due to the nature of the primary studies. Standards aimed at improving the quality of primary studies on the prognosis of health conditions have been created, but these standards are often not adequately followed causing confusion about how to judge the evidence.

METHODS

This article presents a proposed adaptation of Grading of Recommendations Assessment, Development and Evaluation (GRADE), which was developed to rate the quality of evidence in intervention research, to judge the quality of prognostic evidence.

RESULTS

We propose modifications to the GRADE framework for use in prognosis research along with illustrative examples from an ongoing systematic review in the pediatric pain literature. We propose six factors that can decrease the quality of evidence (phase of investigation, study limitations, inconsistency, indirectness, imprecision, publication bias) and two factors that can increase it (moderate or large effect size, exposure-response gradient).

CONCLUSIONS

We describe criteria for evaluating the potential impact of each of these factors on the quality of evidence when conducting a review including a narrative synthesis or a meta-analysis. These recommendations require further investigation and testing.