Geographic variation in implantable cardioverter-defibrillator use and heart failure survival

Relationship between ICD implantation volume and treatment parameters of patients receiving an ICD with remote monitoring

BACKGROUND

Both highly specialized heart centres and less specialized hospitals care for patients with implantable ICDs/CRT-Ds with remote monitoring.

OBJECTIVE

To investigate potential differences in patient treatment according to centre's ICD implantation volume.

METHODS

Based on their 2012 ICD/CRT-D implantation volume, centres enrolled in the NORDIC ICD trial in Germany were assigned to one of three groups: high- (HV, n= 345), medium- (MV, n= 340) or low-volume (LV, n= 189).

RESULTS

The HV-centres had a significant higher CRT-D proportion (41.7%; LV: 36.5%; MV: 23.2%; P𝑔𝑙𝑜𝑏𝑎𝑙< 0.001), significant shorter median procedure duration (49 min; MV: 58 min; LV: 60 min; P𝑔𝑙𝑜𝑏𝑎𝑙< 0.001) but significant longer median hospital stay (4 days; MV and LV: 3 days; P𝑔𝑙𝑜𝑏𝑎𝑙< 0.001) compared to MV- and LV-centres. The X-ray exposure was shorter in MV/HV-centres (MV: 3.4 min; HV: 3.6 min; LV: 5.5 min; P𝑔𝑙𝑜𝑏𝑎𝑙< 0.001). Only 3.5% (LV: 2.6%; HV: 3.5%; MV: 4.1%) patients received at least one delivered inappropriate shock and 2.5% (HV: 2.0%; LV: 2.6%; MV: 2.9%) patients had withheld inappropriate ICD shocks without subsequent inappropriate shock delivery within 24.5 months of median follow-up.

CONCLUSION

Implantation volume-dependent differences were observed in the device selection, procedure duration and x-ray exposure duration. Remote monitoring in combination with adequate response pattern prevented imminent inappropriate shocks in all three groups.

Clinical Profile and Health Disparities in a Multiethnic Cohort of Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Clinical studies of hypertrophic cardiomyopathy are over-represented by individuals of European ethnicity, with less known about other ethnic groups. We investigated differences between patients in a multiethnic Australian hypertrophic cardiomyopathy population.

METHODS

We performed a retrospective cohort study of 836 unrelated hypertrophic cardiomyopathy probands attending a specialized clinic between 2002 and 2020. Major ethnic groups were European (n=611), East Asian (n=75), South Asian (n=58), and Middle Eastern and North African (n=68). The minor ethnicity groups were Oceanian (n=9), People of the Americas (n=7), and African (n=8). One-way ANOVA with Dunnett post hoc test and Bonferroni adjustment were performed.

RESULTS

Mean age of the major ethnic groups was 54.9±16.9 years, and 527 (65%) were male. Using the European group as the control, East Asian patients had a lower body mass index (29 versus 25 kg/m², P<0.0001). South Asians had a lower prevalence of atrial fibrillation (10% versus 31%, P=0.024). East Asians were more likely to have apical hypertrophy (23% versus 6%, P<0.0001) and Middle Eastern and North African patients more likely to present with left ventricular outflow tract obstruction (46% versus 34%, P=0.0003). East Asians were less likely to undergo genetic testing (55% versus 85%, P<0.0001) or have an implantable cardioverter-defibrillator implanted (19% versus 36%, P=0.037). East Asians were more likely to have a causative variant in a gene other than MYBPC3 or MYH7, whereas Middle Eastern and North African and South Asians had the highest rates of variants of uncertain significance (27% and 21%, P<0.0001).

CONCLUSIONS

There are few clinical differences based on ethnicity, but importantly, we identify health disparities relating to access to genetic testing and implantable cardioverter-defibrillator use. Unless addressed, these gaps will likely widen as we move towards precision-medicine-based care of individuals with hypertrophic cardiomyopathy.

Significant regional variation in use of implantable cardioverter-defibrillators in Denmark

AIMS

Implantable cardioverter-defibrillator (ICD) treatment prevents sudden cardiac death in high-risk patients. This study examined geographical variation in ICD implantation rates in Denmark and potential causes of variation.

METHODS AND RESULTS

We obtained numbers of ICD implantations in the 5 Danish regions and 98 municipalities during 2007-13 from the Danish Pacemaker and ICD Registry. Standardized implantation rates (SIRs) were computed as ICD implantations per 1 000 000 person-years, and age- and gender-standardized to the Danish population. We examined associations of the municipal SIR with mean age and Charlson Comorbidity Index score of ICD recipients, percentage of implantations with primary prophylactic indication, and distance from patient residency to ICD implanting centre. Based on 7192 ICD implantations, the nationwide SIR was 186 [95% confidence interval (CI) 182-190], ranging from 170 (95% CI 158-183) in the North Denmark Region to 206 (95% CI 195-218) in the Region of Zealand. Municipalities with higher patient comorbidity scores, higher percentages of implantations with primary prophylactic indication, and shorter distances to ICD implanting centres, had higher SIRs [differences between SIRs of municipalities in highest and lowest quartiles 22 (95% CI 10-34), 45 (95% CI 33-58), and 35 (95% CI 24-47), respectively]. Regional differences in SIRs decreased over time and had become insignificant during 2011-13.

CONCLUSION

Implantable cardioverter-defibrillator implantation rates in Denmark varied significantly between regions but variation decreased during 2007-13. Geographical variation was associated with differences in patient comorbidity score, variation in use of primary prophylactic ICD treatment, and distance to ICD implanting centre.

Admissions to intensive cardiac care units in France in 2014: A cross-sectional, nationwide population-based study

Geographic variation in admission to the intensive cardiac care unit (ICCU) might question about the efficiency and the equity of the healthcare system. The aim was to explain geographic variation in the rate of admission to ICCU for coronary artery disease (CAD) or heart failure (HF) in France.We conducted a retrospective study based on the French national hospital discharge database. All inpatient stays for CAD or HF with an admission to an ICCU in 2014 were included. We estimated population-based age and sex-standardized ICCU admission rates at the department level. We separately modeled the department-level admission rates for HF and CAD using generalized linear models.In all, 61,010 stays for CAD and 27,828 stays for HF had at least 1 ICCU admission. The ICCU admission rates were explained by the admission rate for CAD, by the diabetes prevalence, by the proportion of the population >75 years, and by the drive time to the ICCU.This work sheds light on the finding of substantial geographic variation in the ICCU admission rates for CAD and HF in France. This variation is explained by both the age and the health status of the population and also by the drive time to the closest ICCU for HF. Moreover, ICCU admission for HF might be more prone to unwarranted variations due to medical practice patterns.

Eleven-year trends of inpatient pacemaker implantation in patients diagnosed with sick sinus syndrome

BACKGROUND

Pacemakers (PM) are used for managing sick sinus syndrome (SSS). This study evaluates predictors and trends of PM implantation for SSS.

METHODS

Patients were identified from the National Inpatient Sample dataset (2003-2013). Included patients were ≥18 years old, had a diagnosis of sinus node dysfunction and atrial arrhythmia (i.e., SSS). Patients who died, transferred out, who had prior device, or had a defibrillator or resynchronization therapy device implanted were excluded. Included patients were then stratified by if a PM was implanted. Data regarding SSS, trends of PM utilization, and multivariable models of factors associated with PM implantation are presented.

RESULTS

Note that 328,670 patients satisfied study criteria. This study compared patients who underwent (87.4%) PM implantation to those who did not undergo (12.6%) PM implantation. The annual trends for hospitalization with SSS and PM placement have been decreasing (P <0.001). Variables associated with lower likelihood for PM implantation include young age, female sex, non-Caucasian race, chronic heart failure, Charlson Comorbidity Score ≥1, emergency room and weekend admission, hospital stay ≤3 days, and high cardiology inpatient volume. Greater likelihood for PM implantation was associated with hyperlipidemia, hypertension, and hospitals that were either private, large, Northeastern location, or with high cardiac procedural volume.

CONCLUSIONS

Analyzing 11-year data from a national inpatient database demonstrate a number of relevant variables that impact PM utilization that include not only clinical but also nonclinical variables such as socioeconomic status, gender, and hospital features. Racial and gender bias toward PM implantation are unchanged and persist through 2013.

Geographic and Temporal Variation in Cardiac Implanted Electric Devices to Treat Heart Failure

BACKGROUND

Cardiac implantable electric devices are commonly used to treat heart failure. Little is known about temporal and geographic variation in use of cardiac resynchronization therapy (CRT) devices in usual care settings.

METHODS AND RESULTS

We identified new CRT with pacemaker (CRT-P) or defibrillator generators (CRT-D) implanted between 2008 and 2013 in the United States from a commercial claims database. For each implant, we characterized prior medication use, comorbidities, and geography. Among 17 780 patients with CRT devices (median age 69, 31% women), CRT-Ps were a small and increasing share of CRT devices, growing from 12% to 20% in this study period. Compared to CRT-D recipients, CRT-P recipients were older (median age 76 versus 67), and more likely to be female (40% versus 30%). Pre-implant use of β-blockers and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers was low in both CRT-D (46%) and CRT-P (31%) patients. The fraction of CRT-P devices among all new implants varied widely across states. Compared to the increasing national trend, the share of CRT-P implants was relatively increasing in Kansas and relatively decreasing in Minnesota and Oregon.

CONCLUSIONS

In this large, contemporary heart failure population, CRT-D use dwarfed CRT-P, though the latter nearly doubled over 6 years. Practice patterns vary substantially across states and over time. Medical therapy appears suboptimal in real-world practice.

Geographic variation in the use of catheter ablation for atrial fibrillation among Medicare beneficiaries

BACKGROUND

Catheter ablation for atrial fibrillation is used increasingly in older patients, yet the risks and benefits are not completely understood. With such uncertainty, local medical opinion may influence catheter ablation use.

METHODS

In a 100% sample of Medicare beneficiaries ≥65 years who underwent catheter ablation for atrial fibrillation between January 1, 2007, and December 31, 2009, we investigated variation in use by hospital referral region (HRR) for 20,176 catheter ablation procedures.

RESULTS

Across 274 HRRs, median age was 71.2 years (interquartile range 70.5-71.8), a median of 98% of patients were white, and a median of 39% of patients were women. The median age-standardized prevalence of atrial fibrillation was 77.1 (69.4-84.2) per 1,000 beneficiaries; the median rate of catheter ablation was 3.5 (2.4-4.9) per 1,000 beneficiaries. We found no significant associations between the rate of catheter ablation and prevalence of atrial fibrillation (P = .99), end-of-life Medicare expenditures per capita (P = .09), or concentration of cardiologists (P = .45) but a slight association with Medicare expenditures per capita (linear regression estimate 0.016; 95% CI 0.001-0.031; P = .04). Examined HRR characteristics explained only 2% of the variation in HRR-level rates of catheter ablation (model R(2) = 0.016).

CONCLUSION

The rate of catheter ablation for atrial fibrillation in older patients was low, varied substantially by region, and was not associated with the prevalence of atrial fibrillation, the availability of cardiologists, or end-of-life resource use and was only slightly associated with overall Medicare expenditures per capita.

Cardiac resynchronization therapy: implant rates, temporal trends and relationships with heart failure epidemiology

BACKGROUND

Consensus guidelines define indications for cardiac resynchronization therapy (CRT), but the variability in implant rates in 'real world' clinical practice, as well as the relationship with the epidemiology of heart failure are not defined.

METHODS AND RESULTS

In Emilia-Romagna, an Italian region with around 4.4 million inhabitants, a registry was instituted to collect data on implanted devices for CRT, with (CRT-D) or without defibrillation (CRT-P) capabilities. Data from all consecutive patients resident in this region who underwent a first implant of a CRT device in years 2006-2010 were collected and standardized (considering each of the nine provinces of the region). The number of CRT implants increased progressively, with a 71% increase in 2010 compared to 2006. Between 84 and 90% of implants were with CRT-D devices. The variability in standardized implant rates among the provinces was substantial and the ratio between the provinces with the highest and the lowest implant rates was always greater than 2. Considering prevalent cases of heart failure in the period 2006-2010, the proportion of patients implanted with CRT per year ranged between 0.23 and 0.30%.

CONCLUSIONS

The application in 'real world' clinical practice of CRT in heart failure is quite heterogeneous, with substantial variability even among areas belonging to the same region, with the need to make the access to this treatment more equitable. Despite the increased use of CRT, its overall rate of adoption is low, if a population of prevalent heart failure patients is selected on the basis of administrative data on hospitalizations.

Utilization rates of implantable cardioverter-defibrillators for primary prevention of sudden cardiac death: a 2012 calculation for a midwestern health referral region

BACKGROUND

Utilization rates (URs) for implantable cardioverter-defibrillators (ICDs) for primary prevention of sudden cardiac death (PPSCD) are lacking in the community.

OBJECTIVE

The purpose of this study was to establish the ICD UR in central Indiana.

METHODS

A query run on 2 hospitals in a health information exchange database in Indianapolis identified patients between 2011 and 2012 with left ventricular ejection fraction (EF) ≤0.35. ICD eligibility and utilization were determined from chart review.

RESULTS

We identified 1863 patients with at least 1 low EF study. Two cohorts were analyzed: 1672 patients without and 191 patients with International Classification of Diseases, Ninth Revision, Clinical Modification procedure code 37.94 for ICD placement. We manually reviewed a stratified (by hospital) random sample of 300 patients from the no-ICD procedure code cohort and found that 48 (16%) had no ICD but had class I indications for ICD. Eight of 300 (2.7%) actually had ICD implantation for PPSCD. Review of all 191 patients in the ICD procedure code cohort identified 70 with ICD implantation for PPSCD. The ICD UR (ratio between patients with ICD for PPSCD and all with indication) was 38% overall (95% confidence interval [CI] 28%-49%). URs were 48% for males (95% CI 34%-61%), 21% for females (95% CI 16%-26%, P = .0002 vs males), 40% for whites (95% CI 27%-53%), and 37% for blacks (95% CI 28%-46%, P = .66 vs whites).

CONCLUSION

ICD UR is 38% among patients meeting class I indications, suggesting further opportunities for improving guideline compliance. This study also illustrates limitations in calculating ICD UR using large electronic repositories without hands-on chart review.

Assessing the outcomes of implantable cardioverter defibrillator treatment in a real world setting: results from hospital record data

BACKGROUND

A plethora of clinical studies have assessed the benefits of implantable cardioverter defibrillators (ICDs) and supported their use in clinical practice. However, evidence on the safety and efficacy of ICDs appears insufficient to support expansion of their use in clinical practice, and more information on their impact in real life settings is warranted. This paper aims to investigate the impact of ICDs using a large administrative dataset reflecting actual clinical practice.

METHODS

Data were obtained from the hospital discharge database of the Friuli Venezia Giulia region in Italy containing patient-level information on 169,488 cases. Data on mortality outside hospital were obtained from regional sources. Exact matching method was used to estimate the outcomes associated with ICDs: mortality, length of stay, re-hospitalization and regional expenditure. The method was applied in two steps. First, patients with ICDs were matched with those without using the following: age class (by 5 years), gender, year of admission, type of admission (day hospital vs. ordinary) and primary diagnosis. In the second step, matching included also Charlson Comorbidities Index. Exact matching average treatment effect on the treated (ATT) was used as a main measure of impact.

RESULTS

Compared with matched controls, treatment with ICDs was associated with lower mortality (absolute risk reduction 10.6% at 1 year and 8.3% at 2 and 8.4% at 3 years, p < 0.001 and hazard ratio 0.80, p < 0.001), greater regional expenditure at index hospitalization (ATT: €9459.64, p < 0.001) and during follow up (ATT: €1707.29, p < 0.001) and higher re-hospitalization rate (ATT: 0.53, p < 0.001). No significant difference was found for length of stay (9.07 vs. 8.86 days). The results were maintained after more restrictive matching was applied.

CONCLUSIONS

Assessing the impact of innovative, expensive medical technologies on the basis of real world data is warranted, especially when there are barriers to implementation. Hospital administrative datasets can be of great value when a technology such as the ICD is implemented in a relatively small sample of patients, to allow use of exact matching techniques.

A review of geographic variation and Geographic Information Systems (GIS) applications in prescription drug use research

BACKGROUND

While understanding geography's role in healthcare has been an area of research for over 40 years, the application of geography-based analyses to prescription medication use is limited. The body of literature was reviewed to assess the current state of such studies to demonstrate the scale and scope of projects in order to highlight potential research opportunities.

OBJECTIVE

To review systematically how researchers have applied geography-based analyses to medication use data.

METHODS

Empiric, English language research articles were identified through PubMed and bibliographies. Original research articles were independently reviewed as to the medications or classes studied, data sources, measures of medication exposure, geographic units of analysis, geospatial measures, and statistical approaches.

RESULTS

From 145 publications matching key search terms, forty publications met the inclusion criteria. Cardiovascular and psychotropic classes accounted for the largest proportion of studies. Prescription drug claims were the primary source, and medication exposure was frequently captured as period prevalence. Medication exposure was documented across a variety of geopolitical units such as countries, provinces, regions, states, and postal codes. Most results were descriptive and formal statistical modeling capitalizing on geospatial techniques was rare.

CONCLUSION

Despite the extensive research on small area variation analysis in healthcare, there are a limited number of studies that have examined geographic variation in medication use. Clearly, there is opportunity to collaborate with geographers and GIS professionals to harness the power of GIS technologies and to strengthen future medication studies by applying more robust geospatial statistical methods.