Flexible evaluation of surrogacy in platform studies.

Trial-level surrogates are useful tools for improving the speed and cost effectiveness of trials but surrogates that have not been properly evaluated can cause misleading results. The evaluation procedure is often contextual and depends on the type of trial setting. There have been many proposed methods for trial-level surrogate evaluation, but none, to our knowledge, for the specific setting of platform studies. As platform studies are becoming more popular, methods for surrogate evaluation using them are needed. These studies also offer a rich data resource for surrogate evaluation that would not normally be possible. However, they also offer a set of statistical issues including heterogeneity of the study population, treatments, implementation, and even potentially the quality of the surrogate. We propose the use of a hierarchical Bayesian semiparametric model for the evaluation of potential surrogates using nonparametric priors for the distribution of true effects based on Dirichlet process mixtures. The motivation for this approach is to flexibly model relationships between the treatment effect on the surrogate and the treatment effect on the outcome and also to identify potential clusters with differential surrogate value in a data-driven manner so that treatment effects on the surrogate can be used to reliably predict treatment effects on the clinical outcome. In simulations, we find that our proposed method is superior to a simple, but fairly standard, hierarchical Bayesian method. We demonstrate how our method can be used in a simulated illustrative example (based on the ProBio trial), in which we are able to identify clusters where the surrogate is, and is not useful. We plan to apply our method to the ProBio trial, once it is completed.

Cross-direct effects in settings with two mediators.

When multiple mediators are present, there are additional effects that may be of interest beyond the well-known natural (NDE) and controlled direct effects (CDE). These effects cross the type of control on the mediators, setting one to a constant level and one to its natural level, which differs across subjects. We introduce five such estimands for the cross-CDE and -NDE when two mediators are measured. We consider both the scenario where one mediator is influenced by the other, referred to as sequential mediators, and the scenario where the mediators do not influence each other. Such estimands may be of interest in immunology, as we discuss in relation to measured immunological responses to SARS-CoV-2 vaccination. We provide identifying expressions for the estimands in observational settings where there is no residual confounding, and where intervention, outcome, and mediators are of arbitrary type. We further provide tight symbolic bounds for the estimands in randomized settings where there may be residual confounding of the outcome and mediator relationship and all measured variables are binary.

Comparative risk of serious infection with vedolizumab vs anti-TNF in inflammatory bowel disease: results from nationwide Swedish registers.

OBJECTIVES: We aimed to assess the risk of serious infection in inflammatory bowel disease (IBD) patients treated with vedolizumab, compared to those treated with anti-tumor necrosis factors (TNF) and the general population. METHODS: In this Swedish cohort study, treatment episodes were identified from nationwide health registers. We used Cox regression with propensity score-matched cohorts to estimate hazard ratios (HRs) for incident serious infections, defined as infections requiring hospital admission. RESULTS: During 1376 treatment-episodes in Crohn's disease, the rate of serious infections per 100 person-years (PY) was 5.18 (95%CI=3.98-6.63) with vedolizumab vs 3.54 (95%CI=2.50-4.85) with anti-TNF; HR=1.72 (95%CI=1.12-2.65), partly explained by more gastrointestinal infections. Compared to the rate of 0.75/100 PYs (95%CI=0.59-0.92) in a matched general population cohort, vedolizumab demonstrated higher risk (HR=7.00; 95%CI=5.04-9.72).During 1294 treatment-episodes in ulcerative colitis, the corresponding rates were 3.74/100 PYs (95%CI=2.66-5.11) with vedolizumab vs 3.42/100 PYs (95%CI=2.31-4.89) with anti-TNF; HR=0.80 (95%CI=0.47-1.36) during the initial 1.1 years and HR=2.03 (95%CI=0.65-6.32) after 1.1 years (truncated due to non-proportional hazards). Pneumonia accounted for 40% of all infections among anti-TNF whereas no case was observed among vedolizumab episodes. Compared to the rate of 0.69/100 PYs (95%CI=0.53-0.87) in a matched general population cohort, vedolizumab showed an HR of 5.45 (95%CI=3.67-8.11). CONCLUSIONS: Vedolizumab was associated with increased risks of serious infections compared to anti-TNF in Crohn's disease, but not in ulcerative colitis. Nonetheless, the panorama of serious infections seemed to differ between the drugs. Our findings underscore the importance of clinical awareness of infections and the safety profile of the two therapies.

Inverse probability of treatment weighting with generalized linear outcome models for doubly robust estimation.

There are now many options for doubly robust estimation; however, there is a concerning trend in the applied literature to believe that the combination of a propensity score and an adjusted outcome model automatically results in a doubly robust estimator and/or to misuse more complex established doubly robust estimators. A simple alternative, canonical link generalized linear models (GLM) fit via inverse probability of treatment (propensity score) weighted maximum likelihood estimation followed by standardization (the g $$ g $$ -formula) for the average causal effect, is a doubly robust estimation method. Our aim is for the reader not just to be able to use this method, which we refer to as IPTW GLM, for doubly robust estimation, but to fully understand why it has the doubly robust property. For this reason, we define clearly, and in multiple ways, all concepts needed to understand the method and why it is doubly robust. In addition, we want to make very clear that the mere combination of propensity score weighting and an adjusted outcome model does not generally result in a doubly robust estimator. Finally, we hope to dispel the misconception that one can adjust for residual confounding remaining after propensity score weighting by adjusting in the outcome model for what remains 'unbalanced' even when using doubly robust estimators. We provide R code for our simulations and real open-source data examples that can be followed step-by-step to use and hopefully understand the IPTW GLM method. We also compare to a much better-known but still simple doubly robust estimator.

Menopausal hormone therapy and risk of sarcoidosis: a population-based nested case-control study in Sweden.

Sarcoidosis incidence peaks in women between 50 and 60 years old, which coincides with menopause, suggesting that certain sex hormones, mainly estrogen, may play a role in disease development. We investigated whether menopausal hormone therapy (MHT) was associated with sarcoidosis risk in women and whether the risk varied by treatment type. We performed a nested case-control study (2007-2020) including incident sarcoidosis cases from the Swedish National Patient Register (n = 2593) and matched (1:10) to general population controls (n = 20,003) on birth year, county, and living in Sweden at the time of sarcoidosis diagnosis. Dispensations of MHT were obtained from the Swedish Prescribed Drug Register before sarcoidosis diagnosis/matching. Adjusted odds ratios (aOR) of sarcoidosis were estimated using conditional logistic regression. Ever MHT use was associated with a 25% higher risk of sarcoidosis compared with never use (aOR 1.25, 95% CI 1.13-1.38). When MHT type and route of administration were considered together, systemic estrogen was associated with the highest risk of sarcoidosis (aOR 1.51, 95% CI 1.23-1.85), followed by local estrogen (aOR 1.25, 95% CI 1.11-1.42), while systemic estrogen-progestogen combined was associated with the lowest risk compared to never users (aOR 1.12, 95% CI 0.96-1.31). The aOR of sarcoidosis did not differ greatly by duration of MHT use. Our findings suggest that a history of MHT use is associated with increased risk of sarcoidosis, with women receiving estrogen administered systemically having the highest risk.

Confirmatory prediction-driven RCTs in comparative effectiveness settings for cancer treatment.

BACKGROUND: Medical advances in the treatment of cancer have allowed the development of multiple approved treatments and prognostic and predictive biomarkers for many types of cancer. Identifying improved treatment strategies among approved treatment options, the study of which is termed comparative effectiveness, using predictive biomarkers is becoming more common. RCTs that incorporate predictive biomarkers into the study design, called prediction-driven RCTs, are needed to rigorously evaluate these treatment strategies. Although researched extensively in the experimental treatment setting, literature is lacking in providing guidance about prediction-driven RCTs in the comparative effectiveness setting. METHODS: Realistic simulations with time-to-event endpoints are used to compare contrasts of clinical utility and provide examples of simulated prediction-driven RCTs in the comparative effectiveness setting. RESULTS: Our proposed contrast for clinical utility accurately estimates the true clinical utility in the comparative effectiveness setting while in some scenarios, the contrast used in current literature does not. DISCUSSION: It is important to properly define contrasts of interest according to the treatment setting. Realistic simulations should be used to choose and evaluate the RCT design(s) able to directly estimate that contrast. In the comparative effectiveness setting, our proposed contrast for clinical utility should be used.

Increasing Risk of Lymphoma Over Time in Crohn's Disease but Not in Ulcerative Colitis: A Scandinavian Cohort Study.

BACKGROUND & AIMS: Earlier studies have provided varying risk estimates for lymphoma in patients with inflammatory bowel disease (IBD), but often have been limited by detection biases (especially during the first year of follow-up evaluation), misclassification, and small sample size; and rarely reflect modern-day management of IBD. METHODS: We performed a binational register-based cohort study (Sweden and Denmark) from 1969 to 2019. We compared 164,716 patients with IBD with 1,639,027 matched general population reference individuals. Cox regression estimated hazard ratios (HRs) for incident lymphoma by lymphoma subtype, excluding the first year of follow-up evaluation. RESULTS: From 1969 to 2019, 258 patients with Crohn's disease (CD), 479 patients with ulcerative colitis (UC), and 6675 matched reference individuals developed lymphoma. This corresponded to incidence rates of 35 (CD) and 34 (UC) per 100,000 person-years in IBD patients, compared with 28 and 33 per 100,000 person-years in their matched reference individuals. Although both CD (HR, 1.32; 95% CI, 1.16-1.50) and UC (HR, 1.09; 95% CI, 1.00-1.20) were associated with an increase in lymphoma, the 10-year cumulative incidence difference was low even in CD patients (0.08%; 95% CI, 0.02-0.13). HRs have increased in the past 2 decades, corresponding to increasing use of immunomodulators and biologics during the same time period. HRs were increased for aggressive B-cell non-Hodgkin lymphoma in CD and UC patients, and for T-cell non-Hodgkin lymphoma in CD patients. Although the highest HRs were observed in patients exposed to combination therapy (immunomodulators and biologics) or second-line biologics, we also found increased HRs in patients naïve to such drugs. CONCLUSIONS: During the past 20 years, the risk of lymphomas have increased in CD, but not in UC, and were driven mainly by T-cell lymphomas and aggressive B-cell lymphomas.

Confidence bands in survival analysis.

BACKGROUND: Providing estimates of uncertainty for statistical quantities is important for statistical inference. When the statistical quantity of interest is a survival curve, which is a function over time, the appropriate type of uncertainty estimate is a confidence band constructed to account for the correlation between points on the curve, we will call this a simultaneous confidence band. This, however, is not the type of confidence band provided in standard software, which is constructed by joining the confidence intervals at given time points. METHODS: We show that this type of band does not have desirable joint/simultaneous coverage properties in comparison to simultaneous bands. RESULTS: There are different ways of constructing simultaneous confidence bands, and we find that bands based on the likelihood ratio appear to have the most desirable properties. Although there is no standard software available in the three major statistical packages to compute likelihood-based simultaneous bands, we summarise and give code to use available statistical software to construct other simultaneous forms of bands, which we illustrate using a study of colon cancer. CONCLUSIONS: There is a need for more user-friendly statistical software to compute simultaneous confidence bands using the available methods.

Survival stacking with multiple data types using pseudo-observation-based-AUC loss.

There have been many strategies to adapt machine learning algorithms to account for right censored observations in survival data in order to build more accurate risk prediction models. These adaptions have included pre-processing steps such as pseudo-observation transformation of the survival outcome or inverse probability of censoring weighted (IPCW) bootstrapping of the observed binary indicator of an event prior to a time point of interest. These pre-processing steps allow existing or newly developed machine learning methods, which were not specifically developed with time-to-event data in mind, to be applied to right censored survival data for predicting the risk of experiencing an event. Stacking or ensemble methods can improve on risk predictions, but in general, the combination of pseudo-observation-based algorithms, IPCW bootstrapping, IPC weighting of the methods directly, and methods developed specifically for survival has not been considered in the same ensemble. In this paper, we propose an ensemble procedure based on the area under the pseudo-observation-based-time-dependent ROC curve to optimally stack predictions from any survival or survival adapted algorithm. The real application results show that our proposed method can improve on single survival based methods such as survival random forest or on other strategies that use a pre-processing step such as inverse probability of censoring weighted bagging or pseudo-observations alone.

Reproductive and hormonal risk factors for sarcoidosis: a nested case-control study.

BACKGROUND: Sarcoidosis incidence peaks in females around the fifth decade of life, which coincides with menopause, suggesting hormonal factors play a role in disease development. We investigated whether longer exposure to reproductive and hormonal factors is associated with reduced sarcoidosis risk. METHODS: We conducted a matched case-control study nested within the Mammography Screening Project. Incident sarcoidosis cases were identified via medical records and matched to controls on birth and questionnaire date (1:4). Information on hormonal factors was obtained through questionnaires prior to sarcoidosis diagnosis. Multilevel modelling was used to estimate adjusted odds ratios with 95% credible intervals (OR; 95% CI). RESULTS: In total, 32 sarcoidosis cases and 124 controls were included. Higher sarcoidosis odds were associated with older age at menarche (OR 1.19: 95% CI 0.92-1.55), natural menopause versus non-natural (OR 1.53: 95% CI 0.80-2.93), later age at first pregnancy (OR 1.11: 95% CI 0.76-1.63) and ever hormone replacement therapy (HRT) use (OR 1.40: 95% CI 0.76-2.59). Lower odds were associated with older age at menopause (OR 0.90: 95% CI 0.52-1.55), longer duration of oral contraceptive use (OR 0.70: 95% CI 0.45-1.07), longer duration of HRT use (OR 0.61: 95% CI 0.22-1.70), ever local estrogen therapy (LET) use (OR 0.83: 95% CI 0.34-2.04) and longer duration of LET use (OR 0.78: 95% CI 0.21-2.81). However, the CIs could not rule out null associations. CONCLUSION: Given the inconsistency and modest magnitude in our estimates, and that the 95% credible intervals included one, it still remains unclear whether longer estrogen exposure is associated with reduced sarcoidosis risk.

Inflammatory bowel disease and risk of small bowel cancer: a binational population-based cohort study from Denmark and Sweden.

OBJECTIVE: Crohn's disease (CD) is associated with increased risk of small bowel cancer (SBC), but previous studies have been small. We aimed to examine the risk of incident SBC and death from SBC in patients with inflammatory bowel disease (IBD). DESIGN: In a binational, population-based cohort study from Sweden and Denmark of patients with IBD during 1969-2017 and matched reference individuals from the general population, we evaluated the risk of incident SBC and death from SBC. Cox regression was used to estimate adjusted hazard ratios (aHRs). RESULTS: We identified 161 896 individuals with IBD (CD: 47 370; UC: 97 515; unclassified IBD: 17 011). During follow-up, 237 cases of SBC were diagnosed in patients with IBD (CD: 24.4/100 000 person-years; UC: 5.88/100 000 person-years), compared with 640 cases in reference individuals (2.81/100 000 person-years and 3.32/100 000 person-years, respectively). This corresponded to one extra case of SBC in 385 patients with CD and one extra case in 500 patients with UC, followed up for 10 years. The aHR for incident SBC was 9.09 (95% CI 7.34 to 11.3) in CD and 1.85 (95% CI 1.43 to 2.39) in UC. Excluding the first year after an IBD diagnosis, the aHRs for incident SBC decreased to 4.96 in CD and 1.69 in UC. Among patients with CD, HRs were independently highest for recently diagnosed, childhood-onset, ileal and stricturing CD. The relative hazard of SBC-related death was increased in both patients with CD (aHR 6.59, 95% CI 4.74 to 9.15) and patients with UC (aHR 1.57; 95% CI 1.07 to 2.32). CONCLUSION: SBC and death from SBC were more common in patients with IBD, particularly among patients with CD, although absolute risks were low.

Colorectal cancer in ulcerative colitis: a Scandinavian population-based cohort study.

BACKGROUND: Ulcerative colitis (UC) is a risk factor for colorectal cancer (CRC). However, available studies reflect older treatment and surveillance paradigms, and most have assessed risks for incident CRC without taking surveillance and lead-time bias into account, such as by assessing CRC incidence by tumour stage, or stage-adjusted mortality from CRC. We aimed to compare both overall and country-specific risks of CRC mortality and incident CRC among patients with UC. METHODS: In this population-based cohort study of 96 447 patients with UC in Denmark (n=32 919) and Sweden (n=63 528), patients were followed up for CRC incidence and CRC mortality between Jan 1, 1969, and Dec 31, 2017, and compared with matched reference individuals from the general population (n=949 207). Patients with UC were selected from national registers and included in the analysis if they had two or more records with a relevant International Classification of Disease in the patient register (in the country in question) or one such record plus a colorectal biopsy report with a morphology code suggestive of inflammatory bowel disease. For every patient with UC, we selected matched reference individuals from the total population registers of Denmark and Sweden, who were matched for sex, age, birth year, and place of residence. We used Cox regression to compute hazard ratios (HRs) for incident CRC, and for CRC mortality, taking tumour stage into account. FINDINGS: During follow-up, we observed 1336 incident CRCs in the UC cohort (1·29 per 1000 person-years) and 9544 incident CRCs in reference individuals (0·82 per 1000 person-years; HR 1·66, 95% CI 1·57-1·76). In the UC cohort, 639 patients died from CRC (0·55 per 1000 person-years), compared with 4451 reference individuals (0·38 per 1000 person-years; HR 1·59, 95% CI 1·46-1·72) during the same time period. The CRC stage distribution in people with UC was less advanced (p<0·0001) than in matched reference individuals, but taking tumour stage into account, patients with UC and CRC remained at increased risk of CRC death (HR 1·54, 95% CI 1·33-1·78). The excess risks declined over calendar periods: during the last 5 years of follow-up (2013-17, Sweden only), the HR for incident CRC in people with UC was 1·38 (95% CI 1·20-1·60, or one additional case per 1058 patients with UC per 5 years) and the HR for death from CRC was 1·25 (95% CI 1·03-1·51, or one additional case per 3041 patients with UC per 5 years). INTERPRETATION: Compared with those without UC, individuals with UC are at increased risk of developing CRC, are diagnosed with less advanced CRC, and are at increased risk of dying from CRC, although these excess risks have declined substantially over time. There still seems to be room for improvement in international surveillance guidelines. FUNDING: The Swedish Medical Society, Karolinska Institutet, Stockholm County Council, Swedish Research Council, Swedish Foundation for Strategic Research, Independent Research Fund Denmark, Forte Foundation, Swedish Cancer Foundation.

Microscopic Colitis and Risk of Inflammatory Bowel Disease in a Nationwide Cohort Study.

BACKGROUND & AIMS: Microscopic colitis shares pathogenetic mechanisms with inflammatory bowel disease (IBD). We studied the association between microscopic colitis and risk of incident IBD using data from a nationwide cohort study. METHODS: We conducted a prospective cohort study of all adults who received a diagnosis of microscopic colitis from 1990 through 2017 in Sweden and risk of incident IBD. Cases of microscopic colitis (n= 13,957) were identified through Systematized Nomenclature of Medicine codes from the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, which included gastrointestinal pathology reports from all of Sweden's 28 centers. Individuals with microscopic colitis were matched to 5 general population controls (n = 66,820) and to unaffected siblings (n =13,943). Cox regression was used to estimate adjusted hazard ratio (aHRs) and 95% confidence intervals (CIs). RESULTS: Through December of 2017, we identified 323 incident cases of ulcerative colitis (UC) and 108 incident cases of Crohn's disease (CD) in patients with microscopic colitis compared with 94 UC and 42 CD cases in population comparators. Mean times from diagnosis of microscopic colitis to diagnosis of CD was 3.3 ± 3.2 years and to diagnosis of UC was 3.2 ± 3.5 years. In multivariable models, microscopic colitis was associated with an aHR of 12.6 (95% CI 8.8-18.1) for CD, 17.3 (95% CI 13.7-21.8) for UC, and 16.8 (95% CI 13.9-20.3) for IBD. The 10-year absolute excess risks of CD and UC were 0.9 (95% CI 0.7-1.1) and 2.6 (95% CI 2.2-2.9) percentage points, respectively. In sensitivity analyses, comparing patients with microscopic colitis with their unaffected siblings, the aHRs of CD and UC were 5.4 (95% CI 3.2-9.2) and 9.4 (95% CI 6.4-13.8), respectively. CONCLUSIONS: In a population-based study in Sweden, we found a significant increase in risk of incident IBD among patients with microscopic colitis. Future studies should focus on potential mechanisms underlying these observed associations.

Serious Infections in Pediatric Inflammatory Bowel Disease 2002-2017-A Nationwide Cohort Study.

OBJECTIVE: To assess absolute and relative risks of serious infections (resulting in inpatient care) in children with inflammatory bowel disease (IBD) compared with the general population. STUDY DESIGN: We identified children (<18 years of age) with a first diagnosis of IBD in the Swedish nationwide health registry (2002-2017; n = 5767) and individuals from the general population matched for sex, age, calendar year, and place of residence (reference group; n = 58 418). Hazard ratios (HRs) for serious infections were estimated using Cox regression separately in children with ulcerative colitis (n = 2287), Crohn's disease (n = 2365), and IBD unclassified (n = 1115). RESULTS: During 17 408 person-years of follow-up, 672 serious infections (38.6/1000 person-years) occurred among the children with IBD compared with 778 serious infections in the reference group (4.0/1000 person-years; adjusted HR (95% CI), 9.46 [8.53-10.5]). HRs were increased for children with ulcerative colitis 8.48 (7.21-9.98), Crohn's disease 9.30 (7.86-11.0), and IBD unclassified 12.1 (9.66-16.1). HRs were highest in the first year of follow-up (HR = 12.6 [10.7-14.9]), then decreasing to a 4.8-fold increased risk beyond 10 years of follow-up. Particularly high HRs were also seen in children with IBD undergoing surgery. Apart from a high relative risk of gastrointestinal infections resulting in hospitalization, children with IBD were also at an increased risk of opportunistic infections (HR = 11.8 [6.17-22.5]). CONCLUSIONS: Children with IBD have an increased risk of serious infection requiring hospitalization compared with the general population.

Adult-onset inflammatory bowel disease and rate of serious infections compared to the general population: a nationwide register-based cohort study 2002-2017.

OBJECTIVES: To investigate absolute and relative risk of serious infections in adult/elderly inflammatory bowel disease (IBD) diagnosed 2002-2017. METHODS: Nationwide, register-based cohort study of Swedish patients with IBD compared with general population matched reference individuals with regard to time to first serious infection, equal to hospital admission. Multivariable Cox regression estimated hazard ratios (HRs) for any serious infection. Secondary outcomes included site-specific infections, opportunistic infections and sepsis. RESULTS: We identified 47 798 individuals with IBD. During a follow-up of 329 000 person-years, they had 8752 first serious infections (26.6 per 1000 person-years). This compared with an incidence rate of 10.7 per 1000 person-years in matched reference individuals, corresponding to a 2.53-fold increased hazard of serious infections (95%CI = 2.47-2.59). The HR for serious infection in elderly-onset IBD was 2.01 (95%CI = 1.95-2.08). The relative hazard of serious infection was somewhat higher in Crohn's disease (2.94; 95%CI = 2.81-3.06) than in ulcerative colitis (2.24; 95%CI = 2.17-2.31). The HR for serious infections was high in the first year of follow-up (5.17; 95%CI = 4.93-5.42). Individuals with IBD were at a particularly high relative hazard of gastrointestinal and opportunistic infections. The HR for sepsis was 2.47 (95%CI = 2.32-2.63). The relative rates for serious infections in IBD increased in recent years. CONCLUSIONS: Patients with adult-onset IBD are at increased risk of serious infections, particularly gastrointestinal and opportunistic infections. Relative rates were highest just after IBD diagnosis, and seem to have increased in recent years.

Capturing biologic treatment for IBD in the Swedish Prescribed Drug Register and the Swedish National Patient Register - a validation study.

BACKGROUND: It is not known to what extent biologic treatment for IBD is captured in the Swedish Prescribed Drug Register (PDR) and the National Patient Register (NPR). METHODS: A cross-sectional study from July 2005 until 2017, comparing data on biologic treatment in the PDR and the NPR with medical records. We assessed the proportion of started treatment episodes in the medical records that were found in the PDR/NPR ever, within +/- one year and within +/- three months; for any biologic drug, per specific drug (infliximab, adalimumab, golimumab, vedolizumab, ustekinumab), by calendar period (2005-2008, 2009-2012, and 2013-2017) and by study center. For adalimumab, we assessed the validity of end of treatment episodes. RESULTS: Medical records of 1361 patients and 2323 treatment episodes with any biologic were reviewed and 80.1% (95% CI: 78.4-81.7) were ever captured in the PDR/NPR in. A time window of +/- one year or +/- three months reduced the sensitivity to 63.3% (95% CI: 61.3-65.3) and 52.6% (95% CI: 50.5-54.6), respectively. The sensitivity was high (>85%) for the prescribed injection drugs adalimumab, golimumab, and ustekinumab for all time windows and for adalimumab end of treatment, while considerably lower for the infusion drugs infliximab and vedolizumab. CONCLUSIONS: The PDR and the NPR are reliable data sources on treatment with injection biologics in patients with IBD in Sweden. Infliximab and vedolizumab are poorly captured, why PDR/NPR data should only be used after careful consideration of their limitations or complemented by other data sources, e.g., the disease-specific quality register SWIBREG.

Mortality in adult-onset and elderly-onset IBD: a nationwide register-based cohort study 1964-2014.

OBJECTIVES: To examine all-cause and cause-specific mortality in adult-onset and elderly-onset IBD and to describe time trends in mortality over the past 50 years. DESIGN: Swedish nationwide register-based cohort study 1964-2014, comparing mortality in 82 718 incident IBD cases (inpatient and non-primary outpatient care) with 10 times as many matched general population reference individuals (n=801 180) using multivariable Cox regression to estimate HRs. Among patients with IBD, the number of participants with elderly-onset (≥60 years) IBD was 17 873. RESULTS: During 984 330 person-years of follow-up, 15 698/82 718 (19%) of all patients with IBD died (15.9/1000 person-years) compared with 121 095/801 180 (15.1%) of reference individuals, corresponding to an HR of 1.5 for IBD (95% CI=1.5 to 1.5 (HR=1.5; 95% CI=1.5 to 1.5 in elderly-onset IBD)) or one extra death each year per 263 patients. Mortality was increased specifically for UC (HR=1.4; 95% CI=1.4 to 1.5), Crohn's disease (HR=1.6; 95% CI=1.6 to 1.7) and IBD-unclasssified (HR=1.6; 95% CI=1.5 to 1.8). IBD was linked to increased rates of multiple causes of death, including cardiovascular disease (HR=1.3; 1.3 to 1.3), malignancy (HR=1.4; 1.4 to 1.5) and digestive disease (HR=5.2; 95% CI=4.9 to 5.5). Relative mortality during the first 5 years of follow-up decreased significantly over time. Incident cases of 2002-2014 had 2.3 years shorter mean estimated life span than matched comparators. CONCLUSIONS: Adult-onset and elderly-onset patients with UC, Crohn's disease and IBD-unclassified were all at increased risk of death. The increased mortality remained also after the introduction of biological therapies but has decreased over time.

Mortality of Patients With Microscopic Colitis in Sweden.

BACKGROUND & AIMS: Microscopic colitis is one of the most common causes of chronic diarrhea in older populations. We investigated all-cause and cause-specific mortality in patients with microscopic colitis. METHODS: We conducted a nationwide cohort study of all cases of microscopic colitis (n = 14,333) diagnosed from 1990 through 2017 in Sweden. Cases of microscopic colitis were identified using SNOMED codes from gastrointestinal histopathology reports collected from Sweden's 28 pathology departments. Each case of microscopic colitis was matched to 5 population comparators (n = 68,700). Mortality data were ascertained from Sweden's cause of death register. We used Cox proportional hazards modeling to estimate adjusted hazard ratios (aHRs) and 95% CIs. RESULTS: Through December of 2017, we confirmed 3014 deaths in patients with microscopic colitis (27.4/1000 person-years) and 12,534 deaths in matched population comparators (23.3/1000 person-years). This corresponded to a 10-year absolute risk difference of 3.4% (95% CI, 2.1%-4.6%) and an aHR of 1.17 (95% CI, 1.12-1.22). However, further adjustment of models for comorbidity burden reduced the relative risk of death for patients with microscopic colitis (aHR, 0.98; 95% CI, 0.94-1.02). In analyses of cause-specific death, microscopic colitis was associated with an increased risk of gastrointestinal-related death (aHR, 1.68; 95% CI, 1.38-2.05) and infection-related death (aHR, 1.42 ; 95% CI, 1.11-1.83), but not cancer-related death (aHR, 0.83; 95% CI, 0.76-0.91) or cardiovascular-related death (aHR, 1.02; 95% CI, 0.96-1.10). CONCLUSIONS: In a nationwide cohort study in Sweden, we found that patients with microscopic colitis were at increased risk of death. However, the increase appears to be related to higher burden of comorbidities in this population.

Increased Mortality of Patients With Childhood-Onset Inflammatory Bowel Diseases, Compared With the General Population.

BACKGROUND & AIMS: Childhood-onset inflammatory bowel disease (IBD) is believed to be a more severe disease than adult-onset IBD, but there is little information on all-cause and cause-specific mortality in patients with childhood-onset IBD. We performed a population-based cohort study, with 50 years of follow-up, to estimate absolute and relative risks for overall and cause-specific mortality in patients with childhood-onset IBD, during childhood and adulthood. METHODS: We identified children with a diagnosis of IBD (younger than 18 years) in the Swedish nationwide health registers (1964-2014; n = 9442) and individuals from the general population matched for sex, age, calendar year, and place of residence (reference group; n = 93,180). Hazard ratios (HR) for death were estimated using Cox regression separately in patients with ulcerative colitis (n = 4671), Crohn's disease (n = 3780), and IBD unclassified (n = 991). HRs were compared among calendar periods. RESULTS: During 138,690 person-years of follow-up, 294 deaths (2.1/1000 person-years) occurred among the patients with IBD compared with 940 deaths in the reference group (0.7/1000 person-years; adjusted HR, 3.2; 95% confidence interval [CI] 2.8-3.7). Mean age at end of follow-up was 30 years. HRs were increased for patients with ulcerative colitis 4.0, 95% CI 3.4-4.7; Crohn's disease 2.3, 95% CI 1.8-3.0; and IBD unclassified 2.0, 95% CI 1.2-3.4. Among patients younger than 18 years, there were 27 deaths from IBD 4.9, 95% CI 3.0-7.7. Among young adults with IBD, we found no evidence that HRs for death decreased from 1964 through 2014 (P = .90). CONCLUSIONS: Children with IBD have a 3-fold increase in risk of death when followed through adulthood. The relative risk for death has not decreased with development of new drugs for treatment of IBD.

Aim for Clinical Utility, Not Just Predictive Accuracy.

The predictions from an accurate prognostic model can be of great interest to patients and clinicians. When predictions are reported to individuals, they may decide to take action to improve their health or they may simply be comforted by the knowledge. However, if there is a clearly defined space of actions in the clinical context, a formal decision rule based on the prediction has the potential to have a much broader impact. The use of a prediction-based decision rule should be formalized and preferably compared with the standard of care in a randomized trial to assess its clinical utility; however, evidence is needed to motivate such a trial. We outline how observational data can be used to propose a decision rule based on a prognostic prediction model. We then propose a framework for emulating a prediction driven trial to evaluate the clinical utility of a prediction-based decision rule in observational data. A split-sample structure is often feasible and useful to develop the prognostic model, define the decision rule, and evaluate its clinical utility. See video abstract at, http://links.lww.com/EDE/B656.