Obstructive Sleep Apnea Diagnosed According to Apnea/Hypopnea Index or Respiratory Disturbance Index Criterion: Does It Matter?

Keywords

sleep apnea - apnea/hypopnea index - fatigue - depression

Introduction: Sleep disordered breathing (SDB) is defined based on clinical complaints and polysomnography events. Obstructive sleep apnea (OSA) was initially diagnosed based on the apnea hypopnea index (AHI), but the ICSD-3 has defined the respiratory disturbance index (RDI) as the actual diagnostic criteria.

Aim: This study aimed to evaluate and compare clinical outcomes related to daytime function in OSA patients defined by AHI and RDI.

Methods: This study was derived from the Sao Paulo Epidemiological Sleep Study (EPISONO), in its 3rd edition (2007) and follow up edition (2015). A total of 557 individuals had polysomnography evaluated according to the 2012 American Academy of Sleep Medicine Scoring Manual in both editions. The scores of the Epworth Sleepiness Scale (ESS), Chalder Fatigue Scale (CFS), Pittsburgh Sleep Quality Index (PSQI), Beck Anxiety and Depression Inventories (BAI and BDI) and Insomnia Severity Index (ISI) were compared between individuals who sustained the same AHI level in both editions (either AHI < 15 or AHI ≥ 15). We did the same comparison between individuals who had either RDI < 15 or RDI ≥ 15.

Results: The grouping by AHI included 348 participants with AHI < 15 and 107 with AHI ≥ 15; while the grouping by RDI was composed by 335 with RDI < 15 and 118 with RDI ≥ 15. Considering the AHI grouping, there was no statistically significant differences in ESS, PSQI, BDI and ISI scores after 8 years of follow up, but a significant increase in the CFS and BAI scores was observed. Considering the RDI grouping, there was no statistically significant difference on ESS, PSQI and ISI scores after 8 years of follow up, but there was a significant increased on CFS, BAI and BDI.

Conclusions: OSA diagnosed by either AHI or RDI was associated with increase in fatigue levels. However, when OSA was diagnosed according to RDI, a worse depression score was observed. Depression complaints can significantly impair quality of life and should be consider an important SDB outcome.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
15 June 2023