ANN ARBOR, MI — Central sleep apnea (CSA) in veterans is associated with cardiovascular disorders, chronic prescription opioid use and increased hospital admissions related to those issues, according to a new study.

The report in the journal Sleep also pointed out that diagnosis of CSA needs to be more consistent across the VHA and called for standardization of diagnostics methods to accurately diagnose the condition in high-risk populations.1

The study, led by researchers from Clinical Management Research at the VA Ann Arbor, MI, Healthcare System and John D. Dingell VAMC and Wayne State University, both in Detroit, noted that the prevalence and consequences of CSA in adults has not been well described.

They investigators decided to use the large VHA national administrative databases to determine the incidence, clinical correlates and impact of CSA on healthcare utilization in veterans. To do that, the study team analyzed a retrospective cohort of patients with sleep disorders, using outpatient visits and inpatient admissions from fiscal years 2006 through 2012. Patients with CSA were compared to those without the condition.

Researchers reported that the number of newly diagnosed CSA cases increased 5-fold during the time period but pointed out that prevalence was highly variable depending on the VHA site.

Overall, results indicated that important predictors of CSA were:

  • male gender (Odds Ratio(OR)=2.31, 95% C.I.:1.94-2.76, p<0.0001),
  • heart failure(HF) (OR=1.78, 95% C.I.:1.64-1.92, p<0.0001),
  • atrial fibrillation (OR=1.83, 95% C.I.: 1.69-2.00, p<0.0001),
  • pulmonary hypertension (OR=1.38, 95% C.I.:1.19-1.59, p<0.0001),
  • stroke (OR=1.65, 95% C.I.:1.50-1.82, p<0.0001), and chronic prescription opioid use (OR=1.99, 95% C.I.:1.87-2.13, p<0.0001).

Veterans with CSA also were at an increased risk for hospital admissions for cardiovascular disorders compared to the control group (Incidence Rate Ratio(IRR)=1.50, 95% C.I.:1.16-1.95, p=0.002).

Another finding was that the effect of pre-existing heart failure on future admissions was greater in the CSA group (IRR: 4.78,95% C.I.: 3.87-5.91, p<0.0001) compared to the comparison group (IRR=3.32, 95% C.I.: 3.18-3.47, P<0.0001).

In terms of variation of diagnosis rates at VHA facilities, study authors noted, “Our model fit to calculate expected prevalence by site showed that even after accounting for important patient characteristics (demographics, comorbidities, sleep tests, medications), the distribution of CSA diagnosis across the VAMCs greatly differed from what was expected. This suggests that there are unobserved differences between the VAMCs that are driving the variation in the diagnosis of CSA. Potential sources of this unexplained variation include differences in the use of diagnostic thresholds, tools, and definitions for CSA and differences in coding patterns.”

11. Ratz D, Wiitala W, Badr MS, Burns J, Chowdhuri S. Correlates and Consequences Central Sleep Apnea in a National Sample of U.S. Veterans. Sleep. 2018 Mar 28.doi: 10.1093/sleep/zsy058. [Epub ahead of print] PubMed PMID: 29608761.