Restricted Mean Survival Time for Survival Analysis: A Quick Guide for Clinical Researchers

Early parenteral nutrition is associated with improved growth in very low birth weight infants: a retrospective study

OBJECTIVE

To assess the association between early initiation of parenteral nutrition (PN) and body growth in preterm infants with very low birth weight (VLBW).

DESIGN

Causal inference analysis with confounders preselected by causal diagram based on the NeoNutriNet cohort containing data of infants born between 2011 and 2014 from 13 hospitals from 5 continents.

PATIENTS

Neonates with birth weight ≤1500 g.

INTERVENTIONS

PN initiated within the first day of life (early PN) versus within day 2-5 (delayed PN).

MAIN OUTCOME MEASURES

The primary outcome was body weight z-scores at postmenstrual age (PMA) 36 weeks or early discharge or death, whichever comes first (WT z-score END). Secondary outcomes included WT z-scores at week 1 and 4 of life (WT z-scores CA1 and CA4), corresponding growth velocities (GVs), mortality and incidence of necrotising enterocolitis (NEC), and duration and episodes of antibiotic treatment.

RESULTS

In total, 2151 infants were included in this study and 2008 infants were in the primary outcome analysis. Significant associations of early PN were found with WT z-score END (adjusted mean difference, 0.14 (95% CI 0.05 to 0.23)), CA4 (β, 0.09 (0.04 to 0.14)) and CA1 (0.04 (0.01 to 0.08)), and GV PMA 36 weeks (1.02 (0.46 to 1.58)) and CA4 (1.03 (0.56 to 1.49), all p<0.001), but not with GV CA1 (p>0.05). No significant associations with mortality, incidence of NEC or antibiotic use was found (all p>0.05).

CONCLUSIONS

For VLBW infants, PN initiated within the first day of life is associated with improved in-hospital growth.

Injurious Fall Risk Differences Among Older Adults With First-Line Depression Treatments

Importance

One-third of older adults in the US have depression, often treated with psychotherapy and antidepressants. Previous studies suggesting an increased risk of falls and related injuries (FRI) associated with antidepressant use may be affected by confounding by indication or immortal time bias.

Objective

To evaluate the association between FRI risk and first-line treatments in older adults with depression.

Design, Setting, and Participants

This cohort study used a target trial emulation framework with a cloning-censoring-weighting approach with Medicare claims data from 2016 to 2019. Participants included fee-for-service beneficiaries aged 65 years or older with newly diagnosed depression. Data were analyzed from October 1, 2023, to March 31, 2024.

Exposures

First-line depression treatments including psychotherapy, sertraline, escitalopram, citalopram, mirtazapine, duloxetine, trazodone, fluoxetine, bupropion, paroxetine, and venlafaxine.

Main Outcome and Measure

One-year FRI rate, restricted mean survival time (RMST), and adjusted hazard ratio (aHR) with 95% CI.

Results

Among 101 953 eligible beneficiaries (mean [SD] age, 76 [8] years), 63 344 (62.1%) were female, 7404 (7.3%) were Black individuals, and 81 856 (80.3%) were White individuals. Compared with the untreated group, psychotherapy use was not associated with FRI risk (aHR, 0.94 [95% CI, 0.82-1.17]), while other first-line antidepressants were associated with a decreased FRI risk (aHR ranged from 0.74 [95% CI, 0.59-0.89] for bupropion to 0.83 [95% CI, 0.67-0.98] for escitalopram). The FRI incidence ranged from 63 (95% CI, 53-75) per 1000 person-year for those treated with bupropion to 87 (95% CI, 83-90) per 1000 person-year for those who were untreated. The RMST ranged from 349 (95% CI, 346-350) days for those who were untreated to 353 (95% CI, 350-356) days for those treated with bupropion.

Conclusions and Relevance

In this cohort study of older Medicare beneficiaries with depression, first-line antidepressants were associated with a decreased FRI risk compared with untreated individuals. These findings provide valuable insights into their safety profiles, aiding clinicians in their consideration for treating depression in older adults.

Associations between socioeconomic inequalities and progression to psychological and cognitive multimorbidities after onset of a physical condition: a multicohort study

Background

Chronic physical conditions (e.g., heart diseases, diabetes) increase with population ageing, contributing to psychological and cognitive multimorbidities. Yet, little is known about socioeconomic inequalities in this process. We examined the associations between socioeconomic status (SES) and progression to psychological and cognitive multimorbidities after onset of a physical condition.

Methods

We used harmonized individual-level data from five prospective cohort studies across 24 countries in the US, Europe and Asia, with repeated morbidity measurements between 2002 and 2021. Participants with at least one new-onset physical conditions (hypertension, diabetes, heart diseases, stroke, chronic lung diseases, cancer, or arthritis) were followed up for progression to physical-psychological multimorbidity, physical-cognitive multimorbidity, and physical-psychological-cognitive multimorbidity. SES was determined based on educational level and total household wealth at the onset of a physical condition. Time to and incidence rates of progressing psychological and cognitive multimorbidities were estimated in analyses stratified by SES. Fine-Gray subdistribution hazard models and multi-state models were used to estimate the associations between SES and progression to psychological and cognitive multimorbidities.

Findings

Among 20,250 participants aged ≥45 years (mean age at a physical condition onset 65.38 years, standard deviation 8.37) with at least one new-onset physical conditions in the analysis, 7928 (39.2%) progressed to psychological and cognitive multimorbidities during a median follow-up of 8.0 years (168,575 person-years). The mean survival time free from physical-psychological-cognitive multimorbidity was 11.96 years (95% confidence interval 11.57-12.34) in low SES individuals, compared to 15.52 years (15.40-15.63) in high SES individuals, with the corresponding incidence rate of 18.44 (16.32-20.82) and 3.15 (2.48-4.01) per 1000 person-years, respectively. The associations of education, household wealth and SES with multimorbidities followed a dose-dependent relation, with subdistribution hazard ratios per decreasing SES category being 1.24 (1.19-1.29) for physical-psychological multimorbidity, 1.47 (1.40-1.54) for physical-cognitive multimorbidity, and 1.84 (1.72-1.97) for physical-psychological-cognitive multimorbidity. The strongest SES-multimorbidities associations were observed in participants with arthritis, hypertension or diabetes. In multi-state models SES was linked to all five transitions from physical condition to physical-psychological multimorbidity, physical-cognitive multimorbidity and physical-psychological-cognitive multimorbidity.

Interpretation

Socioeconomic inequalities are associated with the progression of a chronic physical condition, with the lower SES groups had both an earlier time to and a higher incidence of psychological and cognitive multimorbidities. These findings underscore the need for more effective equity-oriented policies and healthcare practices to address reduced psychological wellness and cognitive maintenance among individuals with low SES and physical conditions.

Funding

Zhejiang University Hundred Talents Program Research Initiation Fund, Fundamental Research Funds for the Central Universities in China, Wellcome Trust, Medical Research Council, National Institute on Aging, Academy of Finland.

Comparison of Chemoembolization Outcomes Using 70-150 µm and 100-300 µm Drug-Eluting Beads in Treating Small Hepatocellular Carcinoma: A Korean Multicenter Study

OBJECTIVE

To evaluate the outcomes of drug-eluting bead transarterial chemoembolization (DEB-TACE) according to the size of the beads for the treatment of small hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This retrospective study included 212 patients with a single HCC ≤5 cm from five tertiary institutions. One hundred and nine patients were treated with 70-150-µm doxorubicin DEBs (group A), and 103 patients received 100-300-µm doxorubicin DEBs (group B). The initial tumor response (assessed between 3 weeks and 2 months after DEB-TACE), time to local tumor progression (TTLTP), restricted mean duration of complete response (RMDCR), rate of complications, incidence of post-embolization syndrome, and length of hospital stay were compared between the two groups. Logistic regression was used to analyze prognostic factors for initial tumor response.

RESULTS

The initial objective response rates were 91.7% (100/109) and 84.5% (87/103) for groups A and B, respectively (P = 0.101). In the subgroup analysis of tumors ≤3 cm, the initial objective response rates were 94.6% (53/56) and 78.0% (39/50) for groups A and B, respectively (P = 0.012). There was no significant difference in the TTLTP (median, 23.7 months for group A vs. 19.0 months for group B; P = 0.278 [log-rank], 0.190 [multivariable Cox regression]) or RMDCR at 24 months (11.4 months vs. 8.5 months, respectively; P = 0.088). In the subgroup analysis of tumors >3-cm, the RMDCR at 24 months was significantly longer in group A than in group B (11.8 months vs. 5.7 months, P = 0.024). The incidence of mild bile duct dilatation after DEB-TACE was significantly higher in group B than in group A (5.5% [6/109] vs. 18.4% [19/103], P = 0.003).

CONCLUSION

DEB-TACE using 70-150-µm microspheres demonstrated a higher initial objective response rate in ≤3-cm HCCs and a longer RMDCR at 24 months in 3.1-5-cm HCCs compared to larger DEBs (100-300-µm).

Higher ultraviolet light exposure is associated with lower mortality: An analysis of data from the UK biobank cohort study

We aimed to examine associations between ultraviolet (UV) exposure and mortality among older adults in the United Kingdom (UK). We used data from UK Biobank participants with two UV exposures, validated with measured vitamin D levels: solarium use and annual average residential shortwave radiation. Associations between the UV exposures, all-cause and cause-specific mortality were examined as adjusted hazard ratios. The UV exposures were inversely associated with all-cause, cardiovascular disease (CVD) and cancer mortality. Solarium users were also at a lower risk of non-CVD/non-cancer mortality. The benefits of UV exposure may outweigh the risks in low-sunlight countries.

Negative impact of comorbidities on all-cause mortality of patients with psoriasis is partially alleviated by biologic treatment: A real-world case-control study

BACKGROUND

Cardiovascular comorbidities are believed to cause higher mortality in psoriasis patients. Conversely, systemic therapy may improve overall survival.

OBJECTIVE

To evaluate the impact of different comorbidities and therapy on mortality risk of psoriasis patients in the entire population of Alberta, Canada (population 4.37 million).

METHODS

Cohorts of psoriasis cases (n = 18,618) and controls (ambulatory patients matched 1:3 by age and sex) were retrieved from Alberta Health Services Data Repository of Reporting database within the period 2012 to 2019. Cases were stratified according to Charlson Comorbidity Index, and the type of therapy.

RESULTS

Mortality in psoriasis cohort was significantly higher than in the controls (median age of death 72.0 years vs 74.4 years, respectively). Charlson Comorbidity Index and comorbidities were strong predictors of mortality, in particular drug induced liver injury (hazard ratio 1.8, affective bipolar disease, hazard ratio 1.6, and major cardiovascular diseases. Mortality was lower in patients treated with biologics (hazard ratio 0.54).

LIMITATIONS

Some factors (psoriasis type and severity, response to treatment, smoking, alcohol intake) could not be measured.

CONCLUSIONS

Hepatic injury, psychiatric affective disorders and cardiovascular disease were major determinants of overall survival in psoriasis. Biologic therapy was associated with a reduced mortality risk.

Incidence and predictors of diabetic foot ulcer among patients with diabetes mellitus in a diabetic follow-up clinic in Central Ethiopia: a retrospective follow-up study

BACKGROUND

Diabetic foot ulcer is a major medical, social, and economic problem, and a leading cause of hospitalisations, increased morbidity, and mortality. Despite a rising occurrence, there is a dearth of data on the incidence and its predictors.

OBJECTIVE

To assess the incidence and predictors of diabetic foot ulcers among patients with diabetes mellitus in a diabetic follow-up clinic in Central Ethiopia.

DESIGN

Retrospective follow-up study design.

PARTICIPANTS

A total of 418 newly diagnosed diabetes mellitus patients from 1 January 2012 to 31 December 2022. A computer-generated simple random sampling method was used to select the study participants. Data were collected using a structured data extraction checklist. The collected data were entered into Epi Info V.7.2 and exported to STATA V.14 for analysis. To estimate survival time, the Kaplan-Meier method was used, and the survival difference was tested using a log-rank test.

OUTCOME MEASURES

The Cox proportional hazard model was fitted to identify the predictors of diabetic foot ulcer development. The strength of the association was estimated using an adjusted hazard ratio (AHR) with a 95% confidence interval (CI), and statistical significance was proclaimed at a p<0.05.

RESULT

The overall incidence of diabetic foot ulcer was 1.51 cases (95% CI 1.03 to 2.22) per 100 person-years of observation. The cumulative incidence was 6.2% (95% CI 4.1% to 8.6%) over 10 years. The median time of follow-up was 45 months (IQR 21-73). Diastolic blood pressure of 90 mm Hg or above (AHR 2.91, 95% CI 1.25 to 6.77), taking combined medication (AHR 3.24, 95% CI 1.14 to 9.19) and having a peripheral arterial disease (AHR 5.26, 95% CI 1.61 to 17.18) were statistically significant predictors of diabetic foot ulcer development.

CONCLUSION

The risk of occurrence of diabetic foot ulcer was relatively high. Diastolic blood pressure level, combined medication and peripheral arterial disease were independent predictors of diabetic foot ulcer development. Hence, close monitoring and proper interventions are essential.

Fertility-sparing surgery vs standard surgery for early-stage cervical cancer: difference in 5-year life expectancy by tumor size

BACKGROUND

Cervical cancer incidence among premenopausal women is rising, and fertility-sparing surgery serves as an important option for this young population. There is a lack of evidence on what tumor size cutoff should be used to define candidacy for fertility-sparing surgery.

OBJECTIVE

We sought to describe how the association between fertility-sparing surgery (compared with standard surgery) and life expectancy varies by tumor size among patients with cervical cancers measuring ≤4 cm in largest diameter. Our secondary objective was to quantify the probability of undergoing adjuvant radiotherapy among patients who underwent fertility-sparing surgery as a function of tumor size.

STUDY DESIGN

We identified patients in the National Cancer Database aged ≤45 years, diagnosed with stage I cervical cancer with tumors ≤4 cm between 2006 and 2018, who received no preoperative radiation or chemotherapy, and who underwent either fertility-sparing surgery (cone or trachelectomy, either simple or radical) or standard surgery (simple or radical hysterectomy) as their primary treatment. Propensity-score matching was performed to compare patients who underwent fertility-sparing surgery with those who underwent standard surgery. A flexible parametric model was employed to quantify the difference in life expectancy within 5 years of diagnosis (restricted mean survival time) based on tumor size among patients who underwent fertility-sparing and those who underwent standard surgery. In addition, among those who underwent fertility-sparing surgery, a logistic regression model was used to explore the relationship between tumor size and the probability of receiving adjuvant radiation.

RESULTS

A total of 11,946 patients met the inclusion criteria of whom 904 (7.6%) underwent fertility-sparing surgery. After propensity-score matching, 897 patients who underwent fertility-sparing surgery were matched 1:1 with those who underwent standard surgery. Although the 5-year life expectancy was similar among patients who had fertility sparing surgery and those who had standard surgery regardless of tumor sizes, the estimates of life-expectancy differences associated with fertility-sparing surgery were more precise among patients with smaller tumors (1-cm tumor: restricted mean survival time difference, -0.10 months; 95% confidence interval, -0.67 to 0.47) than among those with larger tumors (4-cm tumor: restricted mean survival time difference, -0.11 months; 95% confidence interval, -3.79 to 3.57). The probability of receiving adjuvant radiation increased with tumor size, ranging from 5.6% (95% confidence interval, 3.9-7.9) for a 1-cm tumor to 37% (95% confidence interval, 24.3-51.8) for a 4-cm tumor.

CONCLUSION

Within 5 years of diagnosis, young patients with stage I cancers measuring ≤4 cm had similar survival outcomes after either fertility-sparing surgery or standard surgery. However, because few patients with tumors >2 cm underwent fertility-sparing surgery, a clinically important survival difference could not be excluded in this population.

Graft Survival of En Bloc Deceased Donor Kidneys Transplants Compared With Single Kidney Transplants

BACKGROUND

The US Kidney Allocation System allocates en bloc deceased donor kidney grafts from donors <18 kg in sequence A along with single kidney transplants (SKTs) from kidney donor profile index (KDPI) top 20% donors. Although en bloc grafts outperform SKT grafts holding donor weight constant, it is unclear if en bloc grafts from the smallest pediatric donors perform the same as top 20% KDPI SKTs.

METHODS

Using the Scientific Registry of Transplant Recipients, we compared the donor characteristics and graft survival of en bloc grafts from the smallest donors (<8 kg) and from larger donors (≥8 kg) with SKTs by KDPI sequence for transplants performed in 2021.

RESULTS

Larger donor en blocs had similar 1-y survival to sequence A SKTs estimated by the Kaplan-Meier method (96% versus 96%, P = 0.9), but the smallest donor en blocs had significantly shorter 1-y survival than those SKTs (80% versus 96%, P < 0.01). Using transplants from 2010 to 2012, the smallest donor en blocs had similar 10-y survival to sequence A SKTs (69% versus 64%, P = 0.3).

CONCLUSIONS

These findings suggest that future updates of the Kidney Allocation System should include a score specific to pediatric donors to account for these differences in en bloc graft survival.

Clinician's Approach to Advanced Statistical Methods: Win Ratios, Restricted Mean Survival Time, Responder Analyses, and Standardized Mean Differences

Novel statistical methods have emerged in recent medical literature, which clinicians must understand to properly appraise and integrate evidence into their practice. Some of these key concepts include win ratios, restricted mean survival time, responder analyses, and standardized mean difference. This article offers guidance to busy clinicians on the comprehension and practical applicability of the results to patients. Win ratios provide an alternative method to analyze composite outcomes by prioritizing individual components of the composite; prioritization of the outcomes should be evidence-based, pre-specified, and patient-centered. Restricted mean survival time presents a method to analyze Kaplan-Meier curves when assumptions required for Cox proportional hazards analysis are not met. As it only considers outcomes that occur within a specific timeframe, the duration of follow-up must be appropriately defined and based on prior epidemiologic and mechanistic evidence. Researchers can analyze continuous outcomes with responder analyses, in which participants are dichotomized into "responders" or "non-responders." While clinicians and patients may more easily grasp outcomes analyzed in this way, they should be aware of the loss of information and resulting imprecision, as well as potential to manipulate data presentation. When meta-analyzing continuous outcomes, point estimates can be converted to standardized mean differences to facilitate the combination of data utilizing various outcome measures. However, clinicians may find it challenging to grasp the clinical meaningfulness of a standardized mean difference, and may benefit from converting it to well-known outcomes. By providing the background knowledge of these statistical methods, along with practical applicability, benefits, and inevitable limitations, this article aims to provide clinicians with an approach to appraise the literature and apply the results in clinical practice.

Preconditioning Frailty Phenotype Influences Survival and Relapse for Older Allogeneic Transplantation Recipients

Hematologic malignancies disproportionately affect older adults. Hematopoietic cell transplantation (HCT) is potentially curative, but poor overall survival (OS) has limited its use in older adults. Fried's frailty phenotype (FFP) is a geriatric assessment tool that combines objective and subjective performance measures: gait speed, grip strength, activity level, exhaustion, and weight loss. People meeting ≥3 criteria are classified as frail; 1 or 2 criteria, as pre-frail; and 0 criteria, as fit. To evaluate the association of pre-HCT FFP with post-HCT outcomes, we assessed FFP prior to conditioning for 280 HCT recipients age ≥60 years with acute leukemia or a myeloid neoplasm at 3 institutions. When analyzing survival by age group, patients age ≥70 years had inferior OS compared to patients age 60 to 69 years (P = .002), with corresponding OS estimates of 38.9% (95% confidence interval [CI], 27.8% to 49.9%) and 59.3% (95% CI, 51.9% to 65.9%). Nonrelapse mortality (NRM) also was significantly higher in the older patients (P = .0005); the 2-year cumulative incidences of NRM were 38.5% (95% CI, 27.5% to 49.2%) and 17.2% (95% CI, 12.3% to 22.8%), for older and younger recipients, respectively. The cumulative incidences of relapse did not differ by age group (P = .3435). Roughly one-third (35.5%) of the patients were fit, 57.5% were pre-frail, and 7.5% were frail, with corresponding 2-year OS estimates of 68.4% (95% CI, 57.9% to 76.8%), 45.5% (95% CI, 37.4% to 53.2%), and 45.8% (95% CI, 23.4% to 65.8%) (P = .013). FFP was not significantly associated with NRM, but being frail or pre-frail was associated with a higher rate of disease-related deaths (33.3% and 27.3%, respectively, compared with 17.4% for fit patients; P = .043). In univariate modeling of restricted mean survival time with a 3-year horizon (RMST_3y), the factors that were significantly associated were FFP, age, Karnofsky Performance Status (KPS), Disease Risk Index (DRI), and HCT-specific Comorbidity Index (HCT-CI). Of those factors, only FFP (P = .006), age (P = .006), KPS (P = .004), and DRI (P = .005) were significantly associated in multivariate modeling of RMST_3y. Estimates of RMST_3y were computed and 5 risk-groups were created with survival ranging from 31.4 months for those who were age 60 to 69 years, fit, had KPS 90 to 100, and low/intermediate-risk DRI compared to 10.5 months for those who had high-risk features for all the evaluated factors. In univariate and multivariate analyses for restricted mean time to relapse with a 3-year horizon (RMRT_3y), FFP (pre-frail versus fit, P = .007; frail versus fit, P = .061) and DRI (P = .001) were the only significant factors. Predicted RMRT_3y was longest (30.6 months) for those who were fit and had low/intermediate-risk DRI scores and shortest (19.1 months) for those who were frail and had high-risk or very high-risk DRI scores. Both age and FFP impact survival after HCT. Incorporation of FFP into pre-HCT evaluations may improve decision-making and counseling regarding HCT risk for older adults. Our findings support future trials designed to reverse frailty, such as pre-HCT supervised exercise programs, and correlative analyses to unravel the connection of frailty and relapse to generate future targets for intervention. Finally, exploration of novel HCT platforms to reduce relapse in pre-frail and frail patients, as well as reduce NRM in adults age >70 years, are warranted.

A Tutorial on Net Benefit Regression for Real-World Cost-Effectiveness Analysis Using Censored Data from Randomized or Observational Studies

HIGHLIGHTS

We illustrate the steps involved in carrying out cost-effectiveness analysis using net benefit regressions with possibly censored demo data by providing step-by-step guidance and code applied to a data set.We demonstrate the importance of these new methods by illustrating how naïve methods for handling censoring can lead to biased cost-effectiveness results.

Respiratory exchange ratio overshoot during exercise recovery: a promising prognostic marker in HFrEF

BACKGROUND AND AIMS

Transient increases (overshoot) in respiratory gas analyses have been observed during exercise recovery, but their clinical significance is not clearly understood. An overshoot phenomenon of the respiratory exchange ratio (RER) is commonly observed during recovery from maximal cardiopulmonary exercise testing (CPET), but it has been found reduced in patients with heart failure with reduced ejection fraction (HFrEF). The aim of the study was to analyze the clinical significance of these RER recovery parameters and to understand if these may improve the risk stratification of patients with HFrEF.

METHODS

This cross-sectional study includes HFrEF patients who underwent functional evaluation with maximal CPET for the heart transplant checklist at our Sports and Exercise Medicine Division. RER recovery parameters, including RER overshoot as the percentual increase of RER during recovery (RER mag), have been evaluated after CPET with assessment of hard clinical long-term endpoints (MACEs/deaths and transplant/LVAD-free survival).

RESULTS

A total of 190 patients with HFrEF and 103 controls were included (54.6 ± 11.9 years; 73% male). RER recovery parameters were significantly lower in patients with HFrEF compared to healthy subjects (RER mag 24.8 ± 14.5% vs 31.4 ± 13.0%), and they showed significant correlations with prognostically relevant CPET parameters. Thirty-three patients with HFrEF did not present a RER overshoot, showing worse cardiorespiratory fitness and efficiency when compared with those patients who showed a detectable overshoot (VO2 peak: 11.0 ± 3.1 vs 15.9 ± 5.1 ml/kg/min; VE/VCO2 slope: 41.5 ± 8.7 vs 32.9 ± 7.9; ΔPETCO2: 2.75 ± 1.83 vs 4.45 ± 2.69 mmHg, respectively). The presence of RER overshoot was associated with a lower risk of cardiovascular events and longer transplant-free survival.

CONCLUSION

RER overshoot represents a meaningful cardiorespiratory index to monitor during exercise gas exchange evaluation; it is an easily detectable parameter that could support clinicians to comprehensively interpreting patients' functional impairment and prognosis. CPET recovery analyses should be implemented in the clinical decision-making of advanced HF.

Advanced considerations in survival analysis

Investigation of survival during the follow-up period is common in cardiovascular research and has intrinsic issues that require precise knowledge, such as survival or censoring. Besides, as the follow-up period lengthens and events other than mortality are studied, the analysis becomes more complex, so Kaplan-Meier analyses or Cox models are not always sufficient. In this primer, we provide the reader with detailed information on the interpretation of the most common survival analyses and delve into methods to analyse competing risks or alternatives to the conventional methods when the proportional hazards assumption is not met.

Associations of Life's Essential 8 and fine particulate matter pollution with the incidence of atrial fibrillation

Both unhealthy lifestyle factors and ambient air pollution have been closely linked with the risk of atrial fibrillation (AF). We retrieved 250,898 participants without AF at baseline from UK Biobank. LE8 was determined by 8 metrics, and was characterized as low, moderate and high cardiovascular health (CVH). Exposure to PM2.5 was estimated at the geocoded residential address of each participant. During a median follow-up of 12.46 years, we identified 14,743 (5.9%) incident AF cases. Participants with moderate and high CVH showed a decreased risk of incident AF compared to those with low CVH. Of the LE8 metrics, ideal body mass index (BMI) and blood pressure (BP) were associated with a decrease of 11.57% and 11.46% AF cases. High PM2.5 exposure was associated with an 8% increased risk of AF as compared to low PM2.5 exposure. Compared with those who had low CVH and high PM2.5 exposure, participants with a high CVH and low PM2.5 exposure had the lower AF incidence. Our study found higher CVH is protective, while higher PM2.5 might be one risk factor of AF. Adherence to the LE8 guidelines may help reduce the incidence of AF, especially in those with lower PM2.5 exposure.

Nivolumab adjuvant therapy for esophageal cancer: a review based on subgroup analysis of CheckMate 577 trial

Esophageal cancer is the sixth most common cancer worldwide. Approximately 50% of patients have locally advanced disease. The CROSS and NEOCRTEC5010 trials have demonstrated that neoadjuvant chemoradiotherapy followed by surgery is the standard treatment for patients with resectable disease. However, a pathological complete response is frequently not achieved, and most patients have a poor prognosis. The CheckMate 577 trial demonstrates that nivolumab adjuvant therapy improves disease-free survival in patents without a pathological complete response. However, there are still numerous clinical questions of concern that remain controversial based on the results of the subgroup analysis. In this review, we aim to offer constructive suggestions addressing the clinical concerns raised in the CheckMate 577 trial.

Staging Chest CT in Patients With Early-Stage Colon Cancer: Analysis of Impact on Survival Using Inverse Probability Weighting and Causal Diagram

BACKGROUND. Staging chest CT has been shown to have negligible diagnostic yield for detecting lung metastases in patients with early-stage colon cancer. Nonetheless, staging chest CT may have potential survival benefits, including opportunistic screening of comorbidity and provision of a baseline examination for future comparisons. Evidence is lacking regarding the impact of staging chest CT on survival in patients with early-stage colon cancer. OBJECTIVE. The purpose of this study was to determine whether the performance of staging chest CT affects survival in patients with early-stage colon cancer. METHODS. This retrospective study included patients with early-stage colon cancer (defined as clinical stage 0 or I on staging abdominal CT) at a single tertiary hospital between January 2009 and December 2015. Patients were divided into two groups according to the presence of a staging chest CT examination. To ensure comparability between the two groups, inverse probability weighting was applied to adjust for the confounders derived from a causal diagram. The between-group differences in adjusted restricted mean survival time at 5 years were measured for overall survival, relapse-free survival, and thoracic metastasis-free survival. Sensitivity analyses were performed. RESULTS. A total of 991 patients (618 men and 373 women; median age, 64 years [IQR, 55-71 years]) were included: 606 patients (61.2%) had staging chest CT. For overall survival, the difference between groups in restricted mean survival time at 5 years was not significant (0.4 months [95% CI, -0.8 to 2.1 months]). The differences between groups in restricted mean survival at 5 years were also not significant for relapse-free survival (0.4 months [95% CI, -1.1 to 2.3 months]) and for thoracic metastasis-free survival (0.6 months [95% CI, -0.8 to 2.4 months]). Similar results were observed in sensitivity analyses that tested 3- and 10-year RMST differences, excluded patients who underwent FDG PET/CT during staging workup, and added treatment decision (surgery vs no surgery) to the causal diagram. CONCLUSION. The use of staging chest CT did not affect survival in patients with early-stage colon cancer. CLINICAL IMPACT. Staging chest CT may be omitted from the staging workup for patients with colon cancer of clinical stage 0 or I.

Restricted Mean Survival Time-Can It Be a New Tool in Assessing the Survival of Non-Small Cell Lung Cancer Patients Treated with Immune Checkpoint Inhibitors?

BACKGROUND

Lung cancer (LC) is the first and most lethal cancer in the world; identifying new methods to treat it, such as immune checkpoint inhibitors (ICIs), is needed. ICIs treatment is very effective, but it comes bundled with a series of immune-related adverse events (irAEs). Restricted mean survival time (RMST) is an alternative tool for assessing the patients' survival when the proportional hazard assumption (PH) fails.

METHODS

We included in this analytical cross-sectional observational survey patients with metastatic non-small-cell lung cancer (NSCLC), treated for at least 6 months with ICIs in the first- and second-line settings. Using RMST, we estimated the overall survival (OS) of patients by dividing them into two groups. A multivariate Cox regression analysis was performed to determine the impact of the prognostic factors on OS.

RESULTS

Seventy-nine patients were included (68.4% men, mean age 63.8), and 34/79 (43%) presented irAEs. The OS RMST of the entire group was 30.91 months, with a survival median of 22 months. Thirty-two out of seventy-nine (40.5%) died before we ended our study. The OS RMST and death percentage favored the patients who presented irAEs (long-rank test, p = 0.036). The OS RMST of patients with irAEs was 35.7 months, with a number of deaths of 12/34 (35.29%), while the OS RMST of the patients without irAEs was 17 months, with a number of deaths of 20/45 (44.44%). The OS RMST by the line of treatment favored the first line of treatment. In this group, the presence of irAEs significantly impacted the survival of these patients (p = 0.0083). Moreover, patients that experienced low-grade irAEs had a better OS RMST. This result has to be cautiously regarded because of the small number of patients stratified according to the grades of irAEs. The prognostic factors for the survival were: the presence of irAEs, Eastern Cooperative Oncology Group (ECOG) performance status and the number of organs affected by metastasis. The risk of dying was 2.13 times higher for patients without irAEs than for the patients who presented irAEs, (CI) 95% of 1.03 to 4.39. Moreover, by increasing the ECOG performance status by one point, the risk of death increased by 2.28 times, with a CI 95% of 1.46 to 3.58, while the involvement of more metastatic organs was associated with a 1.60 times increase in the death risk, with a CI 95% of 1.09 to 2.36. Age and the type of tumor were not predictive for this analysis.

CONCLUSIONS

The RMST is a new tool that helps researchers to better address the survival in studies with ICIs treatment where the PH fails, and the long-rank test is less efficient due to the existence of the long-term responses and delayed treatment effects. Patients with irAEs have a better prognosis than those without irAEs in the first-line settings. The ECOG performance status and the number of organs affected by metastasis must be considered when selecting patients for ICIs treatment.

Sex Differences in Survival from Neuroendocrine Neoplasia in England 2012–2018: A Retrospective, Population-Based Study

Pre-clinical studies have suggested sex hormone signalling pathways may influence tumorigenesis in neuroendocrine neoplasia (NEN). We conducted a retrospective, population-based study to compare overall survival (OS) between males and females with NEN. A total of 14,834 cases of NEN diagnosed between 2012 and 2018, recorded in England’s National Cancer Registry and Analysis Service (NCRAS), were analysed. The primary outcome was OS with 5 years maximum follow-up. Multivariable analysis, restricted mean survival time and mediation analysis were performed. Appendiceal, pulmonary and early-stage NEN were most commonly diagnosed in females; stomach, pancreatic, small intestinal, colonic, rectal and later-stage NEN were more often diagnosed in males. Females displayed increased survival irrespective of the stage, morphology or level of deprivation. On average, they survived 3.62 (95% CI 1.73–5.90) to 10.26 (6.6–14.45) months longer than males; this was statistically significant in NEN of the lung, pancreas, rectum and stomach (p < 0.001). The stage mediated improved survival in stomach, lung, and pancreatic NEN but not in rectal NEN. The reasons underlying these differences are not yet understood. Overall, females diagnosed with NEN tend to survive longer than males, and the stage at presentation only partially explains this. Future research, as well as prognostication and treatment, should consider sex as an important factor.

Race and socioeconomic status interact with HPV to influence survival disparities in oropharyngeal squamous cell carcinoma

BACKGROUND

HPV-related oropharyngeal squamous cell carcinoma (OPSCC) is associated with a favorable prognosis, yet patients of color and low socioeconomic status (SES) continue to experience inferior outcomes. We aim to understand how the emergence of HPV has impacted race and SES survival disparities in OPSCC.

METHODS

A retrospective cohort of 18,362 OPSCC cases from 2010 to 2017 was assembled using the SEER (Surveillance, Epidemiology, and End Results) database. Cox proportional regression and Fine and Gray regression models were used to calculate hazard ratios (HRs) adjusting for race, SES, age, subsite, stage, and treatment.

RESULTS

Black patients had lower overall survival than patients of other races in HPV-positive and HPV-negative OPSCC (HR 1.31, 95% CI 1.13-1.53 and HR 1.23, 95% CI 1.09-1.39, respectively). Higher SES was associated with improved survival in all patients. Race had a diminished association with survival among high SES patients. Low SES Black patients had considerably worse survival than low SES patients of other races.

CONCLUSION

Race and SES interact variably across cohorts. High SES was protective of the negative effects of race, although there remains a disparity in outcomes among Black and non-Black patients, even in high SES populations. The persistence of survival disparities suggests that the HPV epidemic has not improved outcomes equally across all demographic groups.

Risk Group Stratification for Recurrence-Free Survival and Early Tumor Recurrence after Radiofrequency Ablation for Hepatocellular Carcinoma

PURPOSE

Although the prognosis after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) may vary according to different risk levels, there is no standardized follow-up protocol according to each patient's risk. This study aimed to stratify patients according to their risk of recurrence-free survival (RFS) and early (≤2 years) tumor recurrence (ETR) after RFA for HCC based on predictive models and nomograms and to compare the survival times of the risk groups derived from the models.

METHODS

Patients who underwent RFA for a single HCC (≤3 cm) between January 2012 and March 2014 (n = 152) were retrospectively reviewed. Patients were classified into low-, intermediate-, and high-risk groups based on the total nomogram points for RFS and ETR, respectively, and compared for each outcome. Restricted mean survival times (RMSTs) in the three risk groups were evaluated for both RFS and ETR to quantitatively evaluate the difference in survival times.

RESULTS

Predictive models for RFS and ETR were constructed with c-indices of 0.704 and 0.730, respectively. The high- and intermediate-risk groups for RFS had an 8.5-fold and 2.9-fold higher risk of events than the low-risk group (both p < 0.001), respectively. The high- and intermediate-risk groups for ETR had a 17.7-fold and 7.0-fold higher risk than the low-risk group (both p < 0.001), respectively. The RMST in the high-risk group was significantly lower than that in the other two groups 9 months after RFA, and that in the intermediate-risk group became lower than that in the low-risk group after 21 months with RFS and 24 months with ETR.

CONCLUSION

Our predictive models were able to stratify patients into three groups according to their risk of RFS and ETR after RFA for HCC. Differences in RMSTs may be used to establish different follow-up protocols for the three risk groups.

Central obesity as assessed by conicity index and a-body shape index associates with cardiovascular risk factors and mortality in kidney failure patients

Background

Anthropometric indices of central obesity, waist circumference (WC), conicity index (CI), and a-body shape index (ABSI), are prognostic indicators of cardiovascular (CV) risk. The association of CI and ABSI with other CV risk indices, markers of nutritional status and inflammation, and clinical outcomes in chronic kidney disease (CKD) stage 5 (CKD5) patients was investigated.

Methods

In a cross-sectional study with longitudinal follow up of 203 clinically stable patients with CKD5 (median age 56 years; 68% males, 17% diabetics, 22% with CV disease, and 39% malnourished), we investigated CI and ABSI and their associations with atherogenic index of plasma (AIP), Framingham CV risk score (FRS), Agatston scoring of coronary artery calcium (CAC) and aortic valve calcium (AVC), handgrip strength (HGS), high sensitivity C-reactive protein (hsCRP) and interleukin-6 (IL-6). CV events (CVE) and all-cause mortality during up to 10-years follow up were analyzed by multivariate survival analysis of restricted mean survival time (RMST).

Results

Chronic kidney disease patients with middle and highest CI and ABSI tertiles (indicating greater abdominal fat deposition), compared to those with the lowest CI and ABSI tertiles, tended to be older, more often men and diabetic, had significantly higher levels of hsCRP, IL-6, AIP, FRS, CAC and AVC scores. CI and ABSI were positively correlated with CAC, FRS, AIP, hsCRP and IL-6. Both CI and ABSI were negatively correlated with HGS. In age-weighted survival analysis, higher CI and ABSI were associated with higher risk of CVE (Wald test = 4.92, p = 0.027; Wald test = 4.95, p = 0.026, respectively) and all-cause mortality (Wald test = 5.24, p = 0.022; Wald test = 5.19, p = 0.023, respectively). In RMST analysis, low vs. high and middle tertiles of CI and ABSI associated with prolonged CVE-free time and death-free time, and these differences between groups increased over time.

Conclusion

Abdominal fat deposit indices, CI and ABSI, predicted CV outcomes and all-cause mortality, and were significantly associated with the inflammatory status in CKD patients.