Impact of variable look-back periods on the incidence rates of chronic diseases using real world data.

PURPOSE: Estimating disease incidence based on secondary data requires a look-back period to exclude patients with pre-existing disease from the incidence risk set. However, the optimal length of the look-back period and its impact on incidence rates are often unknown. We studied the impact of the length of the look-back period on incidence rates of 24 different chronic diseases. METHODS: Everyone residing in Sweden between January 1, 2005 and December 31, 2013 were identified from national registries and followed up to 2 years (through December 31, 2015). Outcome events were identified from inpatient and outpatient hospital contacts and incidence rates were calculated per 100 000 person-years. The length of the look-back period was varied with 6-month increments, starting at 6 months. The maximum look-back period of 9 years was used as reference period. RESULTS: There were 7 943 807 individuals with a look-back period of at least 9 years (mean age 46.5 years) and a mean follow-up time of 1.97 years. Incidence rates were higher across all diseases when restricting the look-back to 1 year compared to 9 years, with a magnitude of overestimation of the incidence rates between 13% (temporal arteritis) and 174% (type 1 diabetes). However, for most diseases the effect of extending the look-back period beyond 3-5 years appeared comparably small. CONCLUSIONS: This study illustrates how short look-back periods cause overestimation of the incidence rates of chronic diseases, suggesting that sensitivity analyses with respect to look-back period are considered, particularly using data sources with limited information on past medical history.

Characteristics and management of very elderly patients with heart failure: a retrospective, population cohort study.

AIMS: Unmet needs exist in the diagnosis and treatment of heart failure (HF) in the elderly population. Our aim was to analyse and compare data of diagnostics and management of very elderly patients (aged ≥85 years) compared with younger patients (aged 18-84 years) with HF in Sweden. METHODS: Incidence of ≥2 HF diagnosis (ICD-10) was identified from primary/secondary care in Uppsala and Västerbotten during 2010-2015 via electronic medical records linked to data from national health registers. Analyses investigated the diagnosis, treatment patterns, hospitalizations and outpatient visits, and mortality. RESULTS: Of 8702 patients, 27.7% were ≥85 years old, women (60.2%); most patients (80.7%) had unknown left ventricular ejection fraction; key co-morbidities comprised anaemia, dementia, and cerebrovascular disease. More very elderly patients received cardiovascular disease (CVD)-related management after diagnosis in primary care (13.6% vs. 6.5%; P < 0.0001), but fewer patients underwent echocardiography (19.3% vs. 42.9%; P < 0.0001). Within 1 year of diagnosis, very elderly patients were less likely to be hospitalized (all-cause admissions per patient: 1.9 vs. 2.3; P < 0.0001; CVD-related admissions per patient: 1.8 vs. 2.1; P = 0.0004) or prescribed an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) plus a ß-blocker (45.2% vs. 56.9%; P < 0.0001) or an ACEI/ARB plus a ß-blocker plus a mineralocorticoid receptor antagonist (15.4% vs. 31.7%; P < 0.0001). One-year mortality was high in patients ≥85 years old, 30.5% (CI: 28.3-32.7%) out of 1797 patients. CONCLUSIONS: Despite the large number of very elderly patients with newly diagnosed HF in Sweden, poor diagnostic work-up and subsequent treatment highlight the inequality of care in this vulnerable population.

Real-world study of flash glucose monitoring among adults with type 2 diabetes within the Swedish National Diabetes Register.

BACKGROUND: The Swedish National Diabetes Register (NDR) initiated registration of the FreeStyle Libre® system and other continuous glucose monitoring (CGM) systems in June 2016. We investigated change in HbA1c for people with type 2 diabetes (T2DM) using FreeStyle Libre in Sweden. METHODS: We included adults with T2DM, registered in the NDR after January 1, 2014, and an index date for first use of FreeStyle Libre of June 2016 or later. Methodology was a before/after comparison of HbA1c within 6 months before the index date versus HbA1c around 6 and 12 months after the index date. RESULTS: 711 adults with T2DM using FreeStyle Libre had HbA1c measurements within the study period. Mean HbA1c was significantly reduced at 6 months (-0.50%-unit) and at 12 months (-0.52%-unit) in this group. Degree of change was negatively correlated to baseline HbA1c. Reductions in HbA1c were observed in incident users of FreeStyle Libre with T2DM who were truly naïve to CGM or had unknown prior experience of CGM, and aged 25-74 years. CONCLUSIONS: This real-world study on the Swedish NDR shows that people with T2DM using FreeStyle Libre system for 6 and 12 months significantly reduced their HbA1c.

Healthcare resource utilisation and costs associated with a heart failure diagnosis: a retrospective, population-based cohort study in Sweden.

OBJECTIVES: To examine healthcare resource use (HRU) and costs among heart failure (HF) patients using population data from Sweden. DESIGN: Retrospective, non-interventional cohort study. SETTING: Two cohorts were identified from linked national health registers (cohort 1, 2005-2014) and electronic medical records (cohort 2, 2010-2012; primary/secondary care patients from Uppsala and Västerbotten). PARTICIPANTS: Patients (aged ≥18 years) with primary or secondary diagnoses of HF (≥2 International Classification of Diseases and Related Health Problems, 10th revision classification) during the identification period of January 2005 to March 2015 were included. OUTCOME MEASURES: HRU across the HF phenotypes was assessed with logistic regression. Costs were estimated based on diagnosis-related group codes and general price lists. RESULTS: Total annual costs of secondary care of prevalent HF increased from SEK 6.23 (€0.60) to 8.86 (€0.85) billion between 2005 and 2014. Of 4648 incident patients, HF phenotype was known for 1715: reduced ejection fraction (HFrEF): 64.5%, preserved ejection fraction (HFpEF): 35.5%. Within 1 year of HF diagnosis, the proportion of patients hospitalised was only marginally higher for HFrEF versus HFpEF (all-cause (95% CI): 64.7% (60.8 to 68.4) vs 63.7% (60.8 to 66.5), HR 0.91, p=0.14; cardiovascular disease related (95% CI): 61.1% (57.1 to 64.8) vs 60.9% (58.0 to 63.7), HR 0.93, p=0.28). Frequency of hospitalisations and outpatient visits per patient declined after the first year. All-cause secondary care costs in the first year were SEK 122 758 (€12 890)/patient/year, with HF-specific care accounting for 69% of the costs. Overall, 10% of the most expensive population (younger; predominantly male; more likely to have comorbidities) incurred ~40% of total secondary care costs. CONCLUSIONS: HF-associated costs and HRU are high, especially during the first year of diagnosis. This is driven by high hospitalisations rates. Understanding the profile of resource-intensive patients being at younger age, male sex and high Charlson comorbidity index scores at the time of the HF diagnosis is most likely a sign of more severe disease.

Recurrent heart failure hospitalizations increase the risk of cardiovascular and all-cause mortality in patients with heart failure in Sweden: a real-world study.

AIMS: Heart failure (HF) is a leading cause of hospitalization and is associated with high morbidity and mortality. We examined the impact of recurrent HF hospitalizations (HFHs) on cardiovascular (CV) mortality among patients with HF in Sweden. METHODS AND RESULTS: Adults with incident HF were identified from linked national health registers and electronic medical records from 01 January 2005 to 31 December 2013 for Uppsala and until 31 December 2014 for Västerbotten. CV mortality and all-cause mortality were evaluated. A time-dependent Cox regression model was used to estimate relative CV mortality rates for recurrent HFHs. Assessment was also done for ejection fraction-based HF phenotypes and for comorbid atrial fibrillation, diabetes, or chronic renal impairment. Overall, 3878 patients with HF having an index hospitalization were included, providing 9691.9 patient-years of follow-up. Patients were relatively old (median age: 80 years) and were more frequently male (55.5%). Compared with patients without recurrent HFHs, the adjusted hazard ratio (HR [95% confidence interval; CI]) for CV mortality and all-cause mortality were statistically significant for patients with one, two, three, and four or more recurrent HFHs. The risk of CV mortality and all-cause mortality increased approximately six-fold in patients with four or more recurrent HFHs vs. those without any HFHs (HR [95% CI]: 6.26 [5.24-7.48] and 5.59 [4.70-6.64], respectively). Similar patterns were observed across the HF phenotypes and patients with comorbidities. CONCLUSIONS: There is a strong association between recurrent HFHs and CV and all-cause mortality, with the risk increasing progressively with each recurrent HFH.

Real-world evidence effect of budesonide+formoterol Spiromax on patients with asthma and chronic obstructive pulmonary disease in Sweden.

Background and Objective: Despite improved asthma and chronic obstructive pulmonary disease (COPD) management, treatment remains inadequate in many patients. Understanding the impact of current treatment in settings outside of controlled trials would add important clinical decision-making information. This study evaluated costs and outcomes associated with budesonide+formoterol (BF) Spiromax® initiation among real-world Swedish patients with asthma and/or COPD. Methods:In this retrospective observational analysis of Swedish patients with asthma and/or COPD, data were collected from the National Patient Register, National Dispensed Drug Register, and Cause of Death Register 1 year before and after initiating BF Spiromax (index date). Outcomes included exacerbation occurrence, treatment patterns, inpatient care, and healthcare costs. Results: The study included 576 patients (asthma: 51.6%; COPD: 32.8%; and asthma and COPD: 15.6%). Following BF Spiromax initiation in asthma patients, there were significant decreases in exacerbations (41.1% to 30.0%; P < 0.001), mean comorbidity-related inpatient visits (0.5 to 0.2; P < 0.001), and inpatient days (1.9 to 0.6; P = 0.006), and a trend toward fewer asthma-related inpatient visits (mean, 0.2 to 0.1; P = 0.056) and asthma-related inpatient days (mean, 0.7 to 0.3; P = 0.060). Increased inpatient utilization was observed in patients with COPD or both diagnoses. All-cause and asthma-/COPD-related medication costs decreased in all groups. Conclusions: After switching to BF Spiromax, asthma patients had fewer exacerbations and hospital visits versus the prior year and COPD patients showed an increase in all-cause and COPD-related healthcare resource utilization. All-cause and asthma-/COPD-related medication costs decreased in all groups after switching to BF Spiromax.

Epidemiology of heart failure and trends in diagnostic work-up: a retrospective, population-based cohort study in Sweden.

PURPOSE: The purpose of this study was to examine the trends in heart failure (HF) epidemiology and diagnostic work-up in Sweden. METHODS: Adults with incident HF (≥2 ICD-10 diagnostic codes) were identified from linked national health registers (cohort 1, 2005-2013) and electronic medical records (cohort 2, 2010-2015; primary/secondary care patients from Uppsala and Västerbotten). Trends in annual HF incidence rate and prevalence, risk of all-cause and cardiovascular disease (CVD)-related 1-year mortality and use of diagnostic tests 6 months before and after first HF diagnosis (cohort 2) were assessed. RESULTS: Baseline demographic and clinical characteristics were similar for cohort 1 (N=174,537) and 2 (N=8,702), with mean ages of 77.4 and 76.6 years, respectively; almost 30% of patients were aged ≥85 years. From 2010 to 2014, age-adjusted annual incidence rate of HF/1,000 inhabitants decreased (from 3.20 to 2.91, cohort 1; from 4.34 to 3.33, cohort 2), while age-adjusted prevalence increased (from 1.61% to 1.72% and from 2.15% to 2.18%, respectively). Age-adjusted 1-year all-cause and CVD-related mortality was higher in men than in women among patients in cohort 1 (all-cause mortality hazard ratio [HR] men vs women 1.07 [95% CI 1.06-1.09] and CVD-related mortality subdistribution HR for men vs women 1.04 [95% CI 1.02-1.07], respectively). While 83.5% of patients underwent N-terminal pro-B-type natriuretic peptide testing, only 36.4% of patients had an echocardiogram at the time of diagnosis, although this increased overtime. In the national prevalent HF population (patients with a diagnosis in 1997-2004 who survived into the analysis period; N=273,999), death from ischemic heart disease and myocardial infarction declined between 2005 and 2013, while death from HF and atrial fibrillation/flutter increased (P<0.0001 for trends over time). CONCLUSION: The annual incidence rate of HF declined over time, while prevalence of HF has increased, suggesting that patients with HF were surviving longer over time. Our study confirms that previously reported epidemiological trends persist and remain to ensure proper diagnostic evaluation and management of patients with HF.