Frailty, Treatments, and Outcomes in Older Patients With Myocardial Infarction: A Nationwide Registry-Based Study

Background Guidelines recommend that patients with myocardial infarction (MI) receive equal care regardless of age. However, withholding treatment may be justified in elderly and frail patients. This study aimed to investigate trends in treatments and outcomes of older patients with MI according to frailty. Methods and Results All patients aged ≥75 years with first-time MI during 2002 to 2021 were identified through Danish nationwide registries. Frailty was categorized using the Hospital Frailty Risk Score. One-year risk and hazard ratios (HRs) for days 0 to 28 and 29 to 365 were calculated for all-cause death. A total of 51 022 patients with MI were included (median, 82 years; 50.2% women). Intermediate/high frailty increased from 26.7% in 2002 to 2006 to 37.1% in 2017 to 2021. Use of treatment increased substantially regardless of frailty: for example, 28.1% to 48.0% (statins), 21.8% to 33.7% (dual antiplatelet therapy), and 7.6% to 28.0% (percutaneous coronary intervention) for high frailty (all P-trend <0.001). One-year death decreased for low frailty (35.1%-17.9%), intermediate frailty (49.8%-31.0%), and high frailty (62.8%-45.6%), all P-trend <0.001. Age- and sex-adjusted 29- to 365-day HRs (2017-2021 versus 2002-2006) were 0.53 (0.48-0.59), 0.62 (0.55-0.70), and 0.62 (0.46-0.83) for low, intermediate, and high frailty, respectively (P-interaction=0.23). When additionally adjusted for treatment, HRs attenuated to 0.74 (0.67-0.83), 0.83 (0.74-0.94), and 0.78 (0.58-1.05), respectively, indicating that increased use of treatment may account partially for the observed improvements. Conclusions Use of guideline-based treatments and outcomes improved concomitantly in older patients with MI, irrespective of frailty. These results indicate that guideline-based management of MI may be reasonable in the elderly and frail.

Long-term mortality, cardiovascular events, and bleeding in stable patients 1 year after myocardial infarction: a Danish nationwide study

AIMS

Outcomes after myocardial infarction (MI) improved during recent decades alongside better risk factor management and implementation of guideline-recommended treatments. However, it is unknown whether this applies to stable patients who are event-free 1 year after MI.

METHODS AND RESULTS

Using nationwide Danish registries, we included all patients with first-time MI during 2000-17 who survived 1 year free from bleeding and cardiovascular events (n = 82 108, median age 64 years, 68.2% male). Follow-up started 1 year after MI and continued through January 2022. Crude risks of mortality, cardiovascular events, and bleeding were estimated in consecutive 3-year periods. Standardized risks were calculated with respect to the distribution of age, sex, comorbidities, and treatments in the latter period. Guideline-recommended treatment use increased during the study period: e.g. statins (68.6-92.5%) and percutaneous coronary intervention (23.9-68.2%). The crude 5-year risks of outcomes decreased (all P-trend <0.001): Mortality, 18.6% (95% confidence interval [CI]: 17.9-19.2) to 12.5% (CI: 11.9-13.1); Recurrent MI, 7.5% (CI: 7.1-8.0) to 5.5% (CI: 5.1-6.0); Bleeding, 3.9% (CI: 3.6-4.3) to 2.7% (CI: 2.4-3.0). Crude 5-year risk of mortality in 2015-17 was as low as 2.6% for patients aged <60 years. Use of guideline-recommended treatments was associated with improved outcomes: After standardization for changes in treatments, 5-year risk of mortality in 2000-02 was 15.5% (CI: 14.9-16.2).

CONCLUSIONS

For patients who were event-free 1 year after MI, the long-term risks of mortality, cardiovascular events, and bleeding decreased significantly, along with an improved use of guideline-recommended treatments between 2000 and 2017. In the most recent period, 1 year after MI, the risk of additional events was lower than previously reported.

Driving restrictions following defibrillator implantation significantly affect recipients' ability to maintain employment

Background

Following defibrillator implantation or in case of ICD therapy, ICD recipients are subject to temporary driving restrictions for private driving. Moreover, the current European recommendations permanently ban professional driving which can significantly alter the recipients' daily life and ability to maintain employment.

Aim and methods

To investigate Danish ICD recipients' perspective on driving restrictions following ICD implantation we distributed a questionnaire to all living ICD patients with a first-time implantation between 2013 and 2016 (n=3913). We linked questionnaire responses with relevant nationwide Danish registers.

Results

Among the 2741 ICD recipients who responded to the questionnaire (response rate 71%, 47% primary prevention, 83% male, median age 67 years), 2513 (92%) held a valid private driver's license at time of implantation and 175 (7%) were actively using a professional driver's license. Almost all (n=2344, 94%) had resumed driving following device implantation. Among those with a driving ban of at least 1 month following either ICD implantation or ICD therapy (n=911), 26% stated the restrictions had severely impeded their daily life, significantly more in the professional drivers group compared with the private drivers (32% vs 24%, p=0.01). Including only patients working prior to implantation (n=465), 27% stated they were very limited and 20% somewhat limited in maintaining employment following implantation due to the driving restrictions. Likewise, 23% were very limited and 19% somewhat limited in getting to their job. Among the active professional drivers (n=175), 58 (33%) stated they had lost their job as a direct consequence of the post-implantation driving restrictions.

Conclusion

Every fourth Danish ICD recipient is severely limited in their daily life due to the driving restrictions. Both professional and private drivers are significantly affected with regards to maintaining employment following implantation, which should be a key focus in rehabilitation programs.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The Danish Heart Foundation and Arvid Nilssons Fond

The impact of statins and RAS inhibitors on the association between delayed antidiabetic treatment and the risk of cardiovascular event in patients with a first HbA1c between 48–57 mmol/mol

Background

In addition to lifestyle intervention, guidelines recommend initiation of antidiabetic (AD) treatment within 3 months of diagnosing type 2 diabetes (T2D). Yet, patients with an initial HbA1c level between 48 and 57 mmol/mol may await effects of lifestyle intervention up to 6 months. Omitting initial AD treatment and any lifestyle-induced remission, may affect initiation of statins and renin-angiotensin system inhibitors (RASi) and, thus, cardiovascular risk.

Purpose

To examine whether omission of initial AD treatment is associated with an increased 5-year risk of first-time major cardiovascular event (MACE: myocardial infarction/stroke/all-cause death) compared with well-controlled patients on AD. Further, whether lower initial use of statins and RASi could explain this excess risk of MACE.

Methods

We used Danish registers to identify patients with a first-measured HbA1c of 48–57 mmol/mol between 2014 and 2020. We included patients aged 40–80 years without prior atherosclerotic disease that were alive the following 180 days (the index date). At date of index, we divided patients into four groups according to AD treatment and achieved HbA1c (mmol/mol): well-controlled (HbA1c ≤47) on AD; poorly controlled (HbA1c ≥48) on AD; remission (HbA1c ≤47) not on AD; poorly controlled (HbA1c ≥48) not on AD. Based on a Cox-regression model and imputations of treatment values of statins and RASi from two logistic regression models, we examined to what extent the observed standardised 5-year risk of MACE within each group could be reduced if each group had the same probability of treatment initiation with statin and RASi as well-controlled patients on AD.

Results

We included 14,206 patients (median age 59 [IQR 51–68] years; 52.0% men) with the following distribution according to AD group: well-controlled on AD: 22.3%; poorly controlled on AD: 14.7%; remission not on AD: 38.3%; poorly controlled not on AD: 24.6%. Patients not on AD had lower probabilities of initiation of statins and RASi compared with patients on AD (Figure 1). Compared with well-controlled on AD, the absolute 5-year risk of MACE was increased with 3.7% (95% CI 1.6–6.1) in poorly controlled on AD; 2.1% (95% CI 0.3–3.8) in remission not on AD; 3.4% (95% CI 1.6–5.3) in poorly controlled not on AD (Figure 1 and 2). If initiation of statins and RASi were the same as in the well-controlled group on AD, patients not on AD could reduce their risk of MACE with 1.0% (95% CI 0.2–1.8) in the remission group and with 2.2% (95% CI 1.2–3.2) in the poorly controlled group (Figure 2).

Conclusions

Patients not on initial AD treatment had an increased 5-year risk of MACE, even among those who experienced remission of T2D. Lower initial use of statin and RASi seem to explain some of the excess risk of MACE in patients not on initial AD treatment. This study emphasizes the need for greater focus on primary prevention with statins and RASi in T2D, especially among patients not on AD treatment.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Research Grant from Steno Diabetes Center Sjaelland

Staphylococcus aureus bacteremia in Danish patients with cardiac implantable electronic devices: an explorative epidemiological study

Background

Device-related infection is the most common serious complication in patients with cardiac implantable electronic devices (CIED). Staphylococcus aureus accounts for up to 30% of CIED-related infections. There is a lack of scientific literature investigating risk of Staphylococcus aureus bacteremia (SAB) in CIED-patients.

Purpose

We aimed to describe the risk of SAB in Danish patients with a CIED through the years 2000–2018 compared to the background population.

Methods

Patients who received a CIED from 2000–2018 were identified from The Danish National Pacemaker and ICD Register. Patients were matched 1:5 on age and gender with the background population. We identified the primary endpoint of first time SAB from The National Danish Staphylococcus Aureus Bacteremia Database. The cumulative incidence of SAB was calculated using the Aalen-Johansen estimator, adding competing risk of death into account. Hazard ratios were estimated by Cox regression models adjusting for age and gender. Crude rates of relapse SAB, defined as a new SAB episode 14–180 days after first SAB, and device extractions were reported for all patients who survived 14 days from SAB diagnosis.

Results

We identified 79,324 CIED-patients (pacemaker (PM) = 61,227; Implantable Cardioverter Defibrillator (ICD) = 11,635; Cardiac resynchronization therapy, PM or ICD (CRT) = 6,364 and 396,590 matched controls (median age 75.5±13.3 years; 61% males). Age and gender distribution differed significantly by device type (age: PM 76.1±12.1; ICD 62.4±13.4; CRT 68.0±11.1; males: PM: 55.6%, ICD% 75.5: CRT: 80.9%). Across a mean follow-up of 5.9 (±4.6) years, we observed first episode of SAB in 1,430 (1.8%) CIED-patients, compared to 2,599 (0.7%) patients in the control population (p&lt;0.001).

The 10-year cumulative incidence of SAB was 1.0% for controls and 2.2% for CIED patients. The risk of SAB differed substantially by device type (Figure 1). Compared to controls and adjusted for age and gender, increasing hazard ratios for SAB were observed with more advanced devices: PM 1.12 (1.11–1.13); ICD 1.36 (1.33–1.39); CRT 1.55 (1.51–1.59). However, CIED-patients with SAB did not have higher 30-day mortality rates than the non-CIED control population with SAB (Controls 34.8%; PM 35.1%; ICD 28.1% CRT 26.1%, p=0.016). Out of all SAB patients who survived 14 days from SAB diagnosis (Controls=1,672; CIED=1,107), relapse SAB occurred in 52 (3.1%) controls and in 51 (4.6%) CIED-patients (PM 4.0%; ICD 5.8%; CRT 6.3%). Device extraction within 14 and 30 days from SAB diagnosis was undertaken in less than 30% of the CIED-patients (PM: 11.3/13.6%; ICD: 22.7/27.5%; CRT: 17.4/20.1%).

Conclusion

The occurrence of SAB was higher in CIED patients compared with controls and increased with more advanced devices. There was no difference in 30-day mortality after SAB between CIED patients and controls. Relapse SAB occurred in less than 7%, despite a low percentage of early device extractions.

Funding Acknowledgement

Type of funding sources: None.

Socioeconomic position and initiation of SGLT-2 inhibitors or GLP-1 receptor agonists in patients with type 2 diabetes – a Danish nationwide observational study

Background

Between 2015 and 2017, Sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucacon-like-peptide-1 receptor agonists (GLP-1 RA) were shown to reduce cardiovascular events in patients with type 2 diabetes and cardiovascular disease. Thus, in 2018, guidelines were updated to favor these drugs in patients with cardiovascular disease and type 2 diabetes. Lower socioeconomic position may adversely affect use of SGLT-2 inhibitors and GLP-1 RA.

Purpose

We aimed to examine socioeconomic differences in initiation of SGLT-2 inhibitors and GLP-1 RA in a contemporary population of patients with type 2 diabetes.

Methods

Through the Danish nationwide registers, we identified all patients with type 2 diabetes who initiated second-line add-on therapy after metformin monotherapy between December 10, 2012, and December 31, 2018. Patients aged 40–79 years and without a history of end-stage renal disease were included. We measured socioeconomic position according to level of income: Low = 1st quartile; Middle = 2nd and 3rd quartile; High = 4th quartile. Based on multivariable logistic regression models adjusted for age, sex, cohabitation status, duration of type 2 diabetes, comorbidities, and cardiovascular medications, we reported the standardised probabilities of initiating each drug class at time of first intensification according to income group and time period: 2012–2014, 2015–2017, and 2018.

Results

The 33,201 patients had a median age of 63 years (interquartile range 53–69). The probability of initiating a SGLT-2 inhibitor or a GLP-1 RA increased over time in all income-groups. In each time period, the standardised probability of initiating a SGLT-2 inhibitor or a GLP-1 RA at time of first intensification increased with increasing income (Figure): in 2012–2014, from 9.6% (95% confidence interval (CI) 8.4–10.9) in the lowest income group to 14.4% (CI 12.9–15.9) in the highest income group; in 2015–2017, from 19.5% (CI 18.3–20.7) to 24.6% (CI 23.3–25.9); in 2018, from 39.9% (CI 37.5–42.3) to 50.7% (CI 48.2–53.1). The absolute difference between high and low income groups increased over time, reaching 10.8% (CI 7.3–14.3) in 2018. A similar trend was observed in both subgroups of patients with and without established cardiovascular disease (data not shown). Initiation of a dipeptidyl peptidase-4 (DPP-4) inhibitor increased with income in the early time periods, but this trend reversed in 2018 (Figure). Initiation of sulfonylureas (SU) showed a consistent inverse association with income in each time period.

Conclusions

Low socioeconomic position was consistently associated with a lower probability of initiation of a GLP-1 RA or a SLGT-2 inhibitor at time of first intensification of antidiabetic treatment, even after guidelines recommended these drugs to patients with established cardiovascular disease. These disparities may adversely affect cardiovascular outcomes in patients with low socioeconomic position.

Funding Acknowledgement

Type of funding sources: None.

P1241Five-year risk of death and readmission for heart failure after implantation of de novo and upgrade cardiac resynchronization therapy devices

Background

De novo implantation of cardiac resynchronization therapy devices with and without an implantable cardiac defibrillator (CRT-D and CRT-P, respectively) is associated with a reduced risk of death and re-admission for heart failure (HF). Whether upgrade to CRT-P/D from a brady pacemaker or an implantable cardiac defibrillator is associated with a similar long-term clinical benefit as de novo implantations is unknown.

Purpose

To compare risk of death and HF readmission in patients receiving a de novo versus upgraded CRT-P/D device.

Methods

From the Danish nationwide administrative registers, we identified all patients who had a CRT-D or CRT-P implanted from 2006 through 2016. Patients were excluded if they had endocarditis within 12 months before implantation. The patients were divided into groups based on whether implantation was an upgrade of a previous device or a de novo implantation. The primary endpoint was the composite of all-cause mortality and HF readmission. Risk of the primary endpoint was assessed with Kaplan Meier estimator and multivariable Cox regression models adjusted for age, sex, ischemic heart disease, diabetes and chronic obstructive pulmonary disease.

Results

The study population comprised 6,324 patients, median age 70 years [25th-75th percentile: 63–77], 22% women. In total, 3,635 patients had a CRT-D, of whom 749 (20.6%) were upgraded from an implantable cardioverter defibrillator device and 2,689 patients had a CRT-P, of whom 496 (18.4%) were upgraded from brady-pacemakers. For patients with CRT-D, five-year event-free survival probability was 35.3% for de novo and 20.4% for upgrades (log-rank p-value<0.001). For patients with CRT-P, five-year event-free survival probability was 38.4% for de novo and 33.7% for upgrades (log-rank p-value=0.29) (Figure 1). In the CRT-D group, upgrade was associated with an increased risk of the primary endpoint, hazard ratio (HR): 1.49 (95%-confidence interval (CI): 1.34–1.65, p<0.001). In the CRT-P group, no significant difference between upgrade and de novo was observed, HR: 1.02 (95%-CI: 0.89–1.18, p=0.72).

Figure 1

Conclusions

Upgrade to a CRT-P was associated with a similar long-term clinical outcome as de novo device implantation. This was in contrast to upgrade CRT-D, which was associated with a worse outcome than de novo implantation. To understand the factors underlying this increased risk, more studies are warranted.

5968Adherence to driving restrictions among patients with an implantable cardioverter defibrillator: insights from a nationwide register-linked survey study

Background

Patients with an implantable cardioverter defibrillator (ICD) are restricted from driving following initial implantation or ICD shock. It is unclear how many patients are aware of, and adhere to, these restrictions.

Purpose

To investigate knowledge of, and adherence to, private and professional driving restrictions in a nationwide cohort of ICD patients.

Methods

A questionnaire was distributed to all living Danish residents ≥18 years who received a first-time ICD between 2013 and 2016 (n=3,913). During this period, Danish guidelines recommended 1 week driving restriction following ICD implantation for primary prevention, and 3 months following either ICD implantation for secondary prevention or appropriate ICD shock, and permanent restriction of professional driving and driving of large vehicles (>3.5 metric tons). Questionnaires were linked with relevant nationwide registries. Logistic regression was applied to identify factors associated with non-adherence.

Results

Of 2,741 questionnaire respondents, 92% (n=2,513) held a valid private driver's license at time of ICD implantation (85% male; 46% primary prevention indication; median age: 67 years (IQR: 59–73)). Of these, 7% (n=175) were actively using a professional driver's license for truck driving (n=73), bus driving (n=45), taxi driving (n=22), large vehicle driving for private use (n=54), or other purposes (n=32) (multiple purposes allowed).

Only 42% of primary prevention patients, 63% of secondary prevention patients, and 72% of patients who experienced an appropriate ICD shock, recalled being informed of any driving restrictions. Only 45% of professional drivers recalled being informed about specific professional driving restrictions (Figure). Most patients (93%, n=2,344) resumed private driving after ICD implantation, more than 30% during the driving restriction period: 34% of primary prevention patients resumed driving within 1 week, 43% of secondary prevention patients resumed driving within 3 months, and 30% of patients who experienced an appropriate ICD shock resumed driving within 3 months. Professional driving was resumed by 35%. Patients who resumed driving within the restricted periods were less likely to report having received information about driving restrictions (all p<0.001) (Figure).

In a multiple logistic regression model, non-adherence was predicted by reporting non-receipt of information about driving restrictions (OR: 3.34, CI: 2.27–4.03), as well as male sex (OR: 1.53, CI: 1.17–2.01), age ≥60 years (OR: 1.20, CI: 1.02–1.64), receipt of a secondary prevention ICD (OR: 2.2, CI: 1.80–2.62), and being the only driver in the household (OR: 1.29, CI: 1.05–1.57).

Conclusion

In this nationwide survey study, many ICD patients were unaware of the driving restrictions, and many ICD patients, including professional drivers, resumed driving within the restricted periods. More focus on communicating driving restrictions might improve adherence.

Acknowledgement/Funding

Danish Heart Foundation, Arvid Nilsson Foundation, Fraenkels Mindefond

4178Insulin treatment is associated with increased risk of device-treated ventricular tachyarrhythmia in patients with diabetes and heart failure

Background

It is debated whether insulin use is associated with a pro-arrhythmic effect. There is paucity of studies investigating this aspect in patients with heart failure (HF), where use of insulin is associated with an increased mortality risk.

Purpose

We aimed to investigate whether patients receiving insulin had higher risk of device-treated ventricular tachyarrhythmia (VTA) in a population of HF patients with medically treated diabetes and primary prevention implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy with defibrillator (CRT-D).

Methods

Information on ICD/CRT-D implantation and therapy, comorbidities, diabetes, diabetes-related complications and medication were obtained through Danish nationwide registers. From 2007 through 2016 we identified all primary prevention ICD/CRT-D implantations in HF patients with diabetes, defined as treatment with antidiabetic medication within one year prior to implantation. Patients were divided into two groups; Insulin treated vs. non-insulin treated patients. Endpoints of interest were VTA, defined as appropriate ICD therapy, and all-cause mortality. Cumulative incidence curves and adjusted Cox proportional Hazards regression analyses were used to assess risk of outcomes. Adjustment variables included age, gender, ischemic heart disease (IHD), left ventricular ejection fraction (LVEF), ICD vs. CRT-D, diuretic use (as a proxy for severity of HF), prior VTA and diabetes-related complications, identified from diagnosis codes for diabetic nephro-, retino-, and neuropathy, multiple diabetic complications and unspecified diabetic complications.

Results

We identified 1240 patients with HF and diabetes with a primary prevention ICD/CRT-D. The majority of patients had type 2 diabetes (94%). Of these 479 patients (39%) were treated with insulin and 761 (61%) were not. Patients were primarily male (85%) with mean age of 66.9±8.3 years, mean LVEF of 25.6±7.5%, 42% had CRT-D and 58% ICD, without differences between the groups. The insulin-treated group had a higher occurrence of diabetes-related complications (81% vs. 42%, p<0.01) and IHD (95% vs. 90%, p<0.01).

During a mean follow-up of 3.1±2.1 years, 74 insulin treated patients (16%) and 86 non-insulin treated patients (11%) experienced VTA (p=0.034), with higher 5-year cumulative incidence of VTA in the insulin group.

Insulin treatment was associated with significantly increased risk of VTA (HR = 1.45; 95% CI [1.04–2.03], p=0.031) and all-cause mortality (HR=1.27; 95% CI [1.03–1.58], p=0.027), as compared with non-insulin treated patients.

Figure 1

Conclusion

In HF patients with diabetes implanted with a primary prevention ICD/CRT-D, treatment with insulin was associated with a significant 45% increased risk of device-treated ventricular tachyarrhythmias and 27% increased risk of all-cause mortality. These findings support further clinical trials to evaluate the safety of insulin in patients with HF and type 2 diabetes.

Importance of beta-blocker dose in prevention of ventricular tachyarrhythmias, heart failure hospitalizations, and death in primary prevention implantable cardioverter-defibrillator recipients: a Danish nationwide cohort study

Aims

There is a paucity of studies investigating a dose-dependent association between beta-blocker therapy and risk of outcome. In a nationwide cohort of primary prevention implantable cardioverter-defibrillator (ICD) patients, we aimed to investigate the dose-dependent association between beta-blocker therapy and risk of ventricular tachyarrhythmias (VT/VF), heart failure (HF) hospitalizations, and death.

Methods and results

Information on ICD implantation, endpoints, comorbidities, beta-blocker usage, type, and dose were obtained through Danish nationwide registers. The two major beta-blockers carvedilol and metoprolol were examined in three dose levels; low (metoprolol ≤ 25 mg; carvedilol ≤ 12.5 mg), intermediate (metoprolol 26-199 mg; carvedilol 12.6-49.9 mg), and high (metoprolol ≥ 200 mg; carvedilol ≥ 50 mg). Time to events was investigated utilizing multivariate Cox models with beta-blocker as a time-dependent variable. From 2007 to 2012, 2935 first-time ICD devices were implanted. During follow-up, 399 patients experienced VT/VF, 728 HF hospitalizations and 361 died. As compared with patients not on beta-blockers, low, intermediate, and high dose had significantly reduced risk of HF hospitalizations {hazard ratio (HR) = 0.68 [0.54-0.87], P = 0.002; HR = 0.53 [0.42-0.66], P < 0.001; HR = 0.43 [0.34-0.54], P < 0.001} and death (HR = 0.47 [0.35-0.64], P < 0.001; HR = 0.29 [0.22-0.39], P = 0.001; HR = 0.24 [0.18-0.33], P < 0.001). For the endpoint of VT/VF, only intermediate and high dose beta-blocker was associated with significantly reduced risk (HR = 0.58 [0.43-0.79], P < 0.001; HR = 0.53 [0.39-0.72], P < 0.001). No significant difference was found between comparable doses of carvedilol and metoprolol on any endpoint (P = 0.06-0.94).

Conclusion

In primary prevention ICD patients, beta-blocker therapy was associated with significantly reduced risk of all endpoints, as compared with patients not on beta-blocker, with the suggestion of a dose-dependent effect. No detectable difference was found between comparable doses of carvedilol and metoprolol.

The impact of co-morbidity burden on appropriate implantable cardioverter defibrillator therapy and all-cause mortality: insight from Danish nationwide clinical registers

AIMS

In a nationwide cohort of primary (PP-ICD) and secondary prevention (SP-ICD) implantable cardioverter defibrillator (ICD) patients, we aimed to investigate the association between co-morbidity burden and risk of appropriate ICD therapy and mortality.

METHODS AND RESULTS

We identified all patients >18 years, implanted with first-time PP-ICD (n = 1873) or SP-ICD (n = 2461) in Denmark from 2007 to 2012. Co-morbidity was identified in administrative registers of hospitalization and drug prescription from pharmacies. Co-morbidity burden was defined as the number of pre-existing non-ICD indication-related co-morbidities including atrial fibrillation, diabetes, chronic obstructive pulmonary disease, chronic renal disease, liver disease, cancer, chronic psychiatric disease, and peripheral and/or cerebrovascular disease, and divided into four groups (co-morbidity burden 0, 1, 2, and ≥3). Through Cox models, we assessed the impact of co-morbidity burden on appropriate ICD therapy and mortality. Increasing co-morbidity burden was not associated with increased risk of appropriate therapy, irrespective of implant indication [all hazard ratios (HRs) 1.0-1.4, P = NS]. Using no co-morbidities as reference, increasing co-morbidity burden was associated with increased mortality risk in PP-ICD patients (co-morbidity burden 1, HR 2.1; comorbidity burden 2, HR 3.7; co-morbidity burden ≥3, HR 6.6) (all P < 0.001) and SP-ICD patients (co-morbidity burden 1, HR 2.2; co-morbidity burden 2, HR 3.8; co-morbidity burden ≥3, HR 5.8). With increasing co-morbidity burden, an increasing frequency of patients died without having utilized their device, with 72% PP-ICD and 45% SP-ICD patients with co-morbidity burden ≥3 dying without prior appropriate ICD therapy.

CONCLUSION

Increasing co-morbidity burden was not associated with increased risk of appropriate ICD therapy. With increasing co-morbidity burden, mortality increased, and a higher proportion of patients died, without ever having utilized their device.