On the rise and fall of the apnea−hypopnea index: A historical review and critical appraisal
Summary
The publication of “The Sleep Apnea Syndromes” by Guilleminault et al. in the 1970s hallmarked the discovery of a new disease entity involving serious health consequences. Obstructive sleep apnea was shown to be the most important disorder among the sleep apnea syndromes (SAS). In the course of time, it was found that the prevalence of obstructive sleep apnea reached the proportions of a global epidemic, with a major impact on public health, safety and the economy. Early on, a metric was introduced to gauge the seriousness of obstructive sleep apnea, based on the objective measurement of respiratory events during nocturnal sleep. The apnea index and later on the apnea−hypopnea index, being the total count of overnight respiratory events divided by the total sleep time in hours, were embraced as principle measures to establish the diagnosis of obstructive sleep apnea and to rate its severity. The current review summarises the historical evolution of the apnea−hypopnea index, which has been subject to many changes, and has been criticised for not capturing relevant clinical features of obstructive sleep apnea. In fact, the application of the apnea−hypopnea index as a continuous exposure variable is based on assumptions that it represents a disease state of obstructive sleep apnea and that evocative clinical manifestations are invariably caused by obstructive sleep apnea if the apnea−hypopnea index is above diagnostic threshold. A critical appraisal of the extensive literature shows that both assumptions are invalid. This conclusion prompts a reconsideration of the role of the apnea−hypopnea index as the prime diagnostic metric of clinically relevant obstructive sleep apnea.
- AASM (1999). Sleep-related breathing disorders in adults: Recommendations for syndrome definition and measurement techniques in clinical research. The Report of an American Academy of Sleep Medicine Task Force. Sleep, 22(5), 667–689.
- AASM (2005). Obstructive sleep apnea, adult. In M. Sateia & P. Hauri (Eds.), The international classification of sleep disorders - Diagnostic and coding manual (2nd edn, pp. 51–55). Westchester, IL, USA: American Academy of Sleep Medicine.
- AASM (2014). Obstructive sleep apnea, adult. In M. Sateia (Ed.), The international classification of sleep disorders (3rd ed., pp. 53–62). Darien, IL: American Academy of Sleep Medicine.
- Abuzaid, A. S., Al Ashry, H. S., Elbadawi, A., Ld, H. A., Saad, M., Elgendy, I. Y., … Lal, C. (2017). Meta-analysis of cardiovascular outcomes with continuous positive airway pressure therapy in patients with obstructive sleep apnea. American Journal of Cardiology, 120(4), 693–699. https://doi.org/10.1016/j.amjca rd.2017.05.042
- Arnardottir, E. S., Bjornsdottir, E., Olafsdottir, K. A., Benediktsdottir, B.,& Gislason, T. (2016). Obstructive sleep apnoea in the general population: Highly prevalent but minimal symptoms. European Respiratory Journal, 47(1), 194–202. https://doi.org/10.1183/13993 003.01148 -2015
- Arnardottir, E. S., Verbraecken, J., Gonçalves, M., Gjerstad, M. D., Grote, L., Puertas, F. J., … Parrino, L. (2016). Variability in recording and scoring of respiratory events during sleep in Europe: A need for uniform standards. Journal of Sleep Research, 25(2), 144–157. https://doi.org/10.1111/jsr.12353
- ASDA. (1990). Obstructive sleep apnea syndrome (780.53-0). In A. S. D. Association (Ed.), The international classification of sleep disorders - Diagnostic and coding manual, (1st ed., pp. 52–58). Rochester, MN: American Sleep Disorders Association.
- Benjafield, A. V., Ayas, N. T., Eastwood, P. R., Heinzer, R., Ip, M. S. M., Morrell, M. J., … Malhotra, A. (2019). Estimation of the global prevalence and burden of obstructive sleep apnoea: A literature-based analysis. The Lancet Respiratory Medicine, 7(8), 687–698. https://doi.org/10.1016/S2213 -2600(19)30198 -5
- Berry, D. T., Webb, W. B., & Block, A. J. (1984). Sleep apnea syndrome. A critical review of the apnea index as a diagnostic criterion. Chest, 86(4), 529–531. https://doi.org/10.1378/chest.86.4.529
- Berry, R. B., Brooks, R., Gamaldo, C. E., Harding, S. M., Marcus, C. L., & Vaughn, B. V. (2012a). The AASM manual for the scoring of sleep and associated events. Rules, terminology and technical specifications. Version 2.0. Darien, IL: American Academy of Sleep Medicine.
- Berry, R. B., Brooks, R., Gamaldo, C. E., Harding, S. M., Marcus, C. L., & Vaughn, B. V.(2012b). IV. Visual rules. Part 1: Respiratory rules for adults. In AASM (Ed.), The AASM manual for the scoring of sleep and associated events. Rules, terminology and technical specifications. Version 2.0. Darien, IL: American Academy of Sleep Medicine.
- Berry, R. B., Budhiraja, R., Gottlieb, D. J., Gozal, D., Iber, C., & Kapur, V. K. … American Academy of Sleep Medicina (2012). Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. Deliberations of the Sleep Apnea Definitions Task Force of the American Academy of Sleep Medicine. Journal of Clinical Sleep Medicine, 8(05), 597–619. https://doi.org/10.5664/jcsm.2172
- Bibbins-Domingo, K., Grossman, D. C., Curry, S. J., Davidson, K. W., Epling, J. W., García, F. A. R., … Tseng, C.-W. (2017). Screening for Obstructive Sleep Apnea in Adults: US Preventive Services Task Force Recommendation Statement. JAMA, 317(4), 407–414. https://doi.org/10.1001/jama.2016.20325
- Block, A. J., Boysen, P. G., Wynne, J. W., & Hunt, L. A. (1979). Sleep apnea, hypopnea and oxygen desaturation in normal subjects. A strong male predominance. New England Journal of Medicine,300(10), 513–517. https://doi.org/10.1056/NEJM1 97903 08300 1001
- Boland, L. L., Shahar, E., Iber, C., Knopman, D. S., Kuo, T. F., & Nieto, F. J. (2002). Measures of cognitive function in persons with varying degrees of sleep-disordered breathing: The Sleep Heart Health Study. Journal of Sleep Research, 11(3), 265–272. https://doi.org/10.1046/j.1365-2869.2002.00308.x
- Bonsignore, M. R., Randerath, W., Riha, R., Smyth, D., Gratziou, C., Goncalves, M., & McNicholas, W. T. (2016). New rules on driver licensing for patients with obstructive sleep apnoea: EU Directive 2014/85/EU. European Respiratory Journal, 47(1), 39–41. https://doi.org/10.1183/13993 003.01894 -2015
- Bouloukaki, I., Grote, L., McNicholas, W. T., Hedner, J., Verbraecken, J., Parati, G., … Schiza, S. E. (2020). Mild obstructive sleep apnoea (OSA) increases hypertension risk challenging traditional OSA severity classification. Journal of Clinical Sleep Medicine, (in press). https://doi.org/10.5664/jcsm.8354
- Buchner, N. J., Sanner, B. M., Borgel, J., & Rump, L. C. (2007). Continuous positive airway pressure treatment of mild to moderate obstructive sleep apnea reduces cardiovascular risk. American Journal of Respiratory and Critical Care Medicine, 176(12), 1274–1280. https://doi.org/10.1164/rccm.20061 1-1588OC
- Burwell, C. S., Robin, E. D., Whaley, R. D., & Bickelmann, A. G. (1956). Extreme obesity associated with alveolar hypoventilation; a Pickwickian syndrome. American Journal of Medicine, 21(5), 811–818. https://doi.org/10.1016/0002-9343(56)90094 -8
- Campos-Rodriguez, F., Martinez-Garcia, M. A., Reyes-Nunez, N., Selma-Ferrer, M. J., Punjabi, N. M., & Farre, R. (2016). Impact of different hypopnea definitions on obstructive sleep apnea severity and cardiovascular mortality risk in women and elderly individuals. Sleep Medicine, 27–28, 54–58. https://doi.org/10.1016/j.sleep.2016.05.020
- Chediak, A. D. (2008). Why CMS approved home sleep testing for CPAP coverage. Journal of Clinical Sleep Medicine, 4(1), 16–18. https://doi.org/10.5664/jcsm.27073
- Collop, N. A., Anderson, W. M., Boehlecke, B., Claman, D., Goldberg, R., & Gottlieb, D. J. … Portable Monitoring Task Force of the American Academy of Sleep Medicine (2007). Clinical guidelines for the use of unattended portable monitors in the diagnosis of obstructive sleep apnea in adult patients. Journal of Clinical Sleep Medicine, 3(7), 737–747.
- Collop, N. A., Tracy, S. L., Kapur, V., Mehra, R., Kuhlmann, D., Fleishman, S. A., & Ojile, J. M. (2011). Obstructive sleep apnea devices for outof-center (OOC) testing: Technology evaluation. Journal of Clinical Sleep Medicine, 7(5), 531–548. https://doi.org/10.5664/JCSM.1328
- Crinion, S. J., Tiron, R., Lyon, G., Zaffaroni, A., Kilroy, H., Doheny, E., … McNicholas, W. T. (2020). Ambulatory detection of sleep apnea using a non-contact biomotion sensor. Journal of Sleep Research, 29(1), e12889. https://doi.org/10.1111/jsr.12889
- Deegan, P. C., & McNicholas, W. T. (1996). Predictive value of clinical features for the obstructive sleep apnoea syndrome. European Respiratory Journal, 9(1), 117–124. https://doi.org/10.1183/09031936.96.09010117
- Dieltjens, M., Verbraecken, J. A., Hedner, J., Vanderveken, O. M., Steiropoulos, P., Kvamme, J. A., … Collaborators, E. (2019). Use of the Clinical Global Impression scale in sleep apnea patients − Results from the ESADA database. Sleep Medicine, 59, 56–65. https://doi.org/10.1016/j.sleep.2018.10.028
- Duce, B., Milosavljevic, J., & Hukins, C. (2015). The 2012 AASM Respiratory Event criteria increase the incidence of hypopneas in an adult sleep center population. Journal of Clinical Sleep Medicine, 11(12), 1425–1431. https://doi.org/10.5664/jcsm.5280
- Eckert, D. J., White, D. P., Jordan, A. S., Malhotra, A., & Wellman, A. (2013). Defining phenotypic causes of obstructive sleep apnea. Identification of novel therapeutic targets. American Journal of Respiratory and Critical Care Medicine, 188(8), 996–1004. https://doi.org/10.1164/rccm.20130 3-0448OC
- Epstein, L. J., Kristo, D., Strollo, P. J. Jr, Friedman, N., Malhotra, A., & Patil, S. P. … Adult Obstructive Sleep Apnea Task Force of the American Academy of Sleep Medicine (2009). Clinical guideline for the evaluation, management and long-term care of obstructive sleep apnea in adults. Journal of Clinical Sleep Medicine, 5(3), 263–276.
- Escourrou, P., Grote, L., Penzel, T., McNicholas, W. T., Verbraecken, J., & Tkacova, R. … Group, E. S (2015). The diagnostic method has a strong influence on classification of obstructive sleep apnea. Journal of Sleep Research, 24(6), 730–738. https://doi.org/10.1111/jsr.12318
- George, C. F., Boudreau, A. C., & Smiley, A. (1996). Simulated driving performance in patients with obstructive sleep apnea. American Journal of Respiratory and Critical Care Medicine, 154(1), 175–181. https://doi.org/10.1164/ajrccm.154.1.8680676
- Gould, G. A., Whyte, K. F., Rhind, G. B., Airlie, M. A., Catterall, J. R., Shapiro, C. M., & Douglas, N. J. (1988). The sleep hypopnea syndrome. American Review of Respiratory Disease, 137(4), 895–898. https://doi.org/10.1164/ajrcc m/137.4.895
- Grote, L., Ploch, T., Heitmann, J., Knaack, L., Penzel, T., & Peter, J. H. (1999). Sleep-related breathing disorder is an independent risk factor for systemic hypertension. American Journal of Respiratory and Critical Care Medicine, 160(6), 1875–1882. https://doi.org/10.1164/ajrccm.160.6.9811054
- Guilleminault, C. (1989). Clinical features and evaluation of obstructive sleep apnea. In M. H. Kryger, T. Roth, & W. C. Dement (Eds), Principles and practice of sleep medicine, (1st ed., pp. 552–558). Philadelphia, PA; W. B. Saunders.
- Guilleminault, C., Stoohs, R., Clerk, A., Cetel, M., & Maistros, P. (1993). A cause of excessive daytime sleepiness. The upper airway resistance syndrome. Chest, 104(3), 781–787. https://doi.org/10.1378/chest.104.3.781
- Guilleminault, C., Tilkian, A., & Dement, W. C. (1976). The sleep apnea syndromes. Annual Review of Medicine, 27, 465–484. https://doi.org/10.1146/annur ev.me.27.020176.002341
- Guilleminault, C., van den Hoed, J., & Mitler, M. M. (1978). Clinical overview of the sleep apnea syndromes. In C. Guilleminault, & W. C.Dement (Eds), Sleep apnea syndromes (pp. 1–12). New York, NY: Alan R. Liss.
- Heinzer, R., Marti-Soler, H., & Haba-Rubio, J. (2016). Prevalence of sleep apnoea syndrome in the middle to old age general population. Lancet Respiratory Medicine, 4(2), e5–6. https://doi.org/10.1016/S2213-2600(16)00006-0
- Heinzer, R., Vat, S., Marques-Vidal, P., Marti-Soler, H., Andries, D., Tobback, N., … Haba-Rubio, J. (2015). Prevalence of sleep-disordered breathing in the general population: The HypnoLaus study. Lancet Respiratory Medicine, 3(4), 310–318. https://doi.org/10.1016/S2213-2600(15)00043-0
- Hirotsu, C., Haba-Rubio, J., Andries, D., Tobback, N., Marques-Vidal, P., Vollenweider, P., … Heinzer, R. (2019). Effect of three hypopnea scoring criteria on OSA prevalence and associated comorbidities in the general population. Journal of Clinical Sleep Medicine, 15(2), 183–194. https://doi.org/10.5664/jcsm.7612
- Ho, V., Crainiceanu, C. M., Punjabi, N. M., Redline, S., & Gottlieb, D. J. (2015). Calibration model for apnea-hypopnea indices: Impact of alternative criteria for hypopneas. Sleep, 38(12), 1887–1892. https://doi.org/10.5665/sleep.5234
- Hudgel, D. W. (1986). "Apnea index": Need for improving the description of respiratory variability during sleep. American Review of Respiratory Disease, 133(4), 708–709. https://doi.org/10.1164/arrd.1986.133.4.708
- Hudgel, D. W. (2016). Sleep apnea severity classification - Revisited. Sleep, 39(5), 1165–1166. https://doi.org/10.5665/sleep.5776
- Iber, C., Ancoli-Israel, S., Chesson, A. L., & Quan, S. F. (2007a). The AASM manual for the scoring of sleep and associated events. Rules, Terminology and Technical Specifications. Westchester, IL: American Academy of Sleep Medicine.
- Iber, C., Ancoli-Israel, S., Chesson, A. L., & Quan, S. F. (2007b). Respiratory rules for adults. In AASM (Ed.), The AASM manual for the scoring of sleep and associated events. Rules, terminology and technical specifications (pp. 45–47). Westchester, IL: American Academy of Sleep Medicine.
- Jung, S. Y., Rhee, E. H., Al-Dilaijan, K. F., Kim, S. W., & Min, J. Y. (2019). Impact of AASM 2012 recommended hypopnea criteria on surgical outcomes for obstructive sleep apnea. Laryngoscope, 130(3), 825–831. https://doi.org/10.1002/lary.28019
- Kapur, V. K., Auckley, D. H., Chowdhuri, S., Kuhlmann, D. C., Mehra, R., Ramar, K., & Harrod, C. G. (2017). Clinical practice guideline for diagnostic testing for adult obstructive sleep apnea: An American Academy of Sleep Medicine Clinical Practice Guideline. Journal of Clinical Sleep Medicine, 13(3), 479–504. https://doi.org/10.5664/jcsm.6506
- Keenan, B. T., Kim, J., Singh, B., Bittencourt, L., Chen, N.-H., Cistulli, P. A., … Pack, A. I. (2018). Recognizable clinical subtypes of obstructive sleep apnea across international sleep centers: A cluster analysis. Sleep, 41(3), https://doi.org/10.1093/sleep /zsx214
- Khalyfa, A., Gileles-Hillel, A., & Gozal, D. (2016). The challenges of precision medicine in obstructive sleep apnea. Sleep Medicine Clinics, 11(2), 213–226. https://doi.org/10.1016/j.jsmc.2016.01.003
- Kingshott, R. N., Engleman, H. M., Deary, I. J., & Douglas, N. J. (1998). Does arousal frequency predict daytime function? European Respiratory Journal, 12(6), 1264–1270.
- Kingshott, R. N., Sime, P. J., Engleman, H. M., & Douglas, N. J. (1995). Self assessment of daytime sleepiness: Patient versus partner. Thorax, 50(9), 994–995. https://doi.org/10.1136/thx.50.9.994
- Kingshott, R. N., Vennelle, M., Hoy, C. J., Engleman, H. M., Deary, I. J., & Douglas, N. J. (2000). Predictors of improvements in daytime function outcomes with CPAP therapy. American Journal of Respiratory and Critical Care Medicine, 161(3 Pt 1), 866–871. https://doi.org/10.1164/ajrccm.161.3.9905053
- Krakow, B., Krakow, J., Ulibarri, V. A., & McIver, N. D. (2014). Frequency and accuracy of "RERA" and "RDI" terms in the Journal of Clinical Sleep Medicine from 2006 through 2012. Journal of Clinical Sleep Medicine, 10(2), 121–124. https://doi.org/10.5664/jcsm.3432
- Kulkas, A., Duce, B., Leppanen, T., Hukins, C., & Toyras, J. (2017). Severity of desaturation events differs between hypopnea and obstructive apnea events and is modulated by their duration in obstructive sleep apnea. Sleep and Breathing, 21(4), 829–835. https://doi.org/10.1007/s11325-017-1513-6
- Lavie, P. (2008). Who was the first to use the term Pickwickian in connection with sleepy patients? History of sleep apnoea syndrome. Sleep Medicine Reviews, 12(1), 5–17. https://doi.org/10.1016/j.smrv.2007.07.008
- Lavie, P., Herer, P., & Hoffstein, V. (2000). Obstructive sleep apnoea syndrome as a risk factor for hypertension: Population study. BMJ, 320(7233), 479–482. https://doi.org/10.1136/bmj.320.7233.479
- Le Bon, O., Hoffmann, G., Tecco, J., Staner, L., Noseda, A., Pelc, I., &Linkowski, P. (2000). Mild to moderate sleep respiratory events: One negative night may not be enough. Chest, 118(2), 353–359. https://doi.org/10.1378/chest.118.2.353
- Li, Q. Y., Berry, R. B., Goetting, M. G., Staley, B., Soto-Calderon, H., Tsai, S. C., … Kuna, S. T. (2015). Detection of upper airway status and respiratory events by a current generation positive airway pressure device. Sleep, 38(4), 597–605. https://doi.org/10.5665/sleep.4578
- Lipford, M. C., Wahner-Roedler, D. L., Welsh, G. A., Mandrekar, J., Thapa, P., & Olson, E. J. (2019). Correlation of the epworth sleepiness scale and sleep-disordered breathing in men and women. Journal of Clinical Sleep Medicine, 15(1), 33–38. https://doi.org/10.5664/jcsm.7564
- Loube, D. I., & Andrada, T. F. (1999). Comparison of respiratory polysomnographic parameters in matched cohorts of upper airway resistance and obstructive sleep apnea syndrome patients. Chest, 115(6), 1519–1524. https://doi.org/10.1378/chest.115.6.1519
- Mansukhani, M. P., Kolla, B. P., Wang, Z., & Morgenthaler, T. I. (2019). Effect of varying definitions of hypopnea on the diagnosis and clinical outcomes of sleep-disordered breathing: A systematic review and meta-analysis. Journal of Clinical Sleep Medicine, 15(5), 687–696. https://doi.org/10.5664/jcsm.7750
- Marin, J. M., Carrizo, S. J., Vicente, E., & Agusti, A. G. (2005). Long-term cardiovascular outcomes in men with obstructive sleep apnoea-hypopnoea with or without treatment with continuous positive airway pressure: An observational study. Lancet, 365(9464), 1046–1053. https://doi.org/10.1016/S0140 -6736(05)71141 -7
- Martinez-Garcia, M. A., Campos-Rodriguez, F., Barbe, F., Gozal, D., & Agusti, A. (2019). Precision medicine in obstructive sleep apnoea. The Lancet Respiratory Medicine, 7(5), 456–464. https://doi.org/10.1016/S2213-2600(19)30044-X
- McEvoy, R. D., Antic, N. A., Heeley, E., Luo, Y., Ou, Q., Zhang, X., … Anderson, C. S. (2016). CPAP for prevention of cardiovascular events in obstructive sleep apnea. New England Journal of Medicine, 375(10), 919–931. https://doi.org/10.1056/NEJMo a1606599
- McNicholas, W. T. (2020). Active management of mild obstructive sleep apnoea: The evidence grows. The Lancet Respiratory Medicine, 8(4), 322–323. https://doi.org/10.1016/S2213-2600(19)30447-3
- Moser, N. J., Phillips, B. A., Berry, D. T., & Harbison, L. (1994). What is hypopnea, anyway? Chest, 105(2), 426–428. https://doi.org/10.1378/chest.105.2.426
- Muraja-Murro, A., Kulkas, A., Hiltunen, M., Kupari, S., Hukkanen, T., Tiihonen, P., … Töyräs, J. (2014). Adjustment of apnea-hypopnea index with severity of obstruction events enhances detection of sleep apnea patients with the highest risk of severe health consequences. Sleep and Breathing, 18(3), 641–647. https://doi.org/10.1007/s11325-013-0927-z
- Norman, R. G., Ahmed, M. M., Walsleben, J. A., & Rapoport, D. M. (1997). Detection of respiratory events during NPSG: Nasal cannula/pressure sensor versus thermistor. Sleep, 20(12), 1175–1184.
- Peker, Y., Glantz, H., Eulenburg, C., Wegscheider, K., Herlitz, J., & Thunstrom, E. (2016). Effect of positive airway pressure on cardiovascular outcomes in coronary artery disease patients with nonsleepy obstructive sleep apnea. The RICCADSA randomized controlled trial. American Journal of Respiratory and Critical Care Medicine, 194(5), 613–620. https://doi.org/10.1164/rccm.20160 1-0088OC
- Peter, J. H., Fuchs, E., Kohler, U., Mayer, J., Meinzer, K., Penzel, T., … von Wichert, P. (1986). Studies in the prevalence of sleep apnea activity (SAA): Evaluation of ambulatory screening results. European Journal of Respiratory Diseases. Supplement, 146, 451–458.
- Pevernagie, D. A., & Verbraecken, J. A. (2015). East, West: Is home best? Sleep Medicine, 16(11), 1432–1433. https://doi.org/10.1016/j.sleep.2015.07.001
- Phillipson, E. A. (1978). Control of breathing during sleep. American Review of Respiratory Disease, 118(5), 909–939. https://doi.org/10.1164/arrd.1978.118.5.909
- Prasad, B., Usmani, S., Steffen, A. D., Van Dongen, H. P. A., Pack, F. M., Strakovsky, I., … Weaver, T. E. (2016). Short-term variability in apnea-hypopnea index during extended home portable monitoring. Journal of Clinical Sleep Medicine, 12(6), 855–863. https://doi.org/10.5664/jcsm.5886
- Punjabi, N. M. (2016). COUNTERPOINT: Is the Apnea-Hypopnea Index the best way to quantify the severity of sleep-disordered breathing? No. Chest, 149(1), 16–19. https://doi.org/10.1378/chest.14-2261
- Punjabi, N. M., Newman, A. B., Young, T. B., Resnick, H. E., & Sanders, M. H. (2008). Sleep-disordered breathing and cardiovascular disease: An outcome-based definition of hypopneas. American Journal of Respiratory and Critical Care Medicine, 177(10), 1150–1155. https://doi.org/10.1164/rccm.20071 2-1884OC
- Randerath, W., Bassetti, C. L., Bonsignore, M. R., Farre, R., Ferini-Strambi, L., Grote, L., … McNicholas, W. T. (2018). Challenges and perspectives in obstructive sleep apnoea: Report by an ad hoc working group of the Sleep Disordered Breathing Group of the European Respiratory Society and the European Sleep Research Society. European Respiratory Journal, 52(3), https://doi.org/10.1183/13993 003.02616 -2017
- Rapoport, D. M. (2016). POINT: Is the Apnea-Hypopnea Index the best way to quantify the severity of sleep-disordered breathing? Yes. Chest, 149(1), 14–16. https://doi.org/10.1378/chest.15-1319
- Redline, S., Kapur, V., Sanders, M., Quan, S., Gottlieb, D., Rapoport, D., … Iber, C. (2000). Effects of varying approaches for identifying respiratory disturbances on sleep apnea assessment. American Journal of Respiratory and Critical Care Medicine, 161(2 Pt 1), 369–374. https://doi.org/10.1164/ajrccm.161.2.9904031
- Redline, S., & Sanders, M. (1997). Hypopnea, a floating metric: Implications for prevalence, morbidity estimates, and case finding. Sleep, 20(12), 1209–1217. https://doi.org/10.1093/sleep /20.12.1209
- Redline, S., & Sanders, M. (1999). A quagmire for clinicians: When technological advances exceed clinical knowledge. Thorax, 54(6), 474–475. https://doi.org/10.1136/thx.54.6.474
- Ruehland, W. R., Rochford, P. D., O'Donoghue, F. J., Pierce, R. J., Singh, P., & Thornton, A. T. (2009). The new AASM criteria for scoring hypopneas: Impact on the apnea hypopnea index. Sleep, 32(2), 150–157. https://doi.org/10.1093/sleep /32.2.150
- Sanchez-de-la-Torre, M., Khalyfa, A., Sanchez-de-la-Torre, A., Martinez-Alonso, M., Martinez-Garcia, M. A., Barcelo, A., … Spanish Sleep, N. (2015). Precision medicine in patients with resistant hypertension and obstructive sleep apnea: Blood pressure response to continuous positive airway pressure treatment. Journal of the American College of Cardiology, 66(9), 1023–1032. https://doi.org/10.1016/j.jacc.2015.06.1315
- Sánchez-de-la-Torre, M., Sánchez-de-la-Torre, A., Bertran, S., Abad, J., Duran-Cantolla, J., Cabriada, V., … Vázquez, M. J. (2019). Effect of obstructive sleep apnoea and its treatment with continuous positive airway pressure on the prevalence of cardiovascular events in patients with acute coronary syndrome (ISAACC study): A randomised controlled trial. The Lancet Respiratory Medicine, 8(4), 359–367. https://doi.org/10.1016/S2213 -2600(19)30271 -1
- Shahar, E. (2014). Apnea-hypopnea index: Time to wake up. Nature and Science of Sleep, 6, 51–56. https://doi.org/10.2147/NSS.S61853
- Smallwood, R. G., Vitiello, M. V., Giblin, E. C., & Prinz, P. N. (1983). Sleep apnea: Relationship to age, sex, and Alzheimer's dementia. Sleep, 6(1), 16–22. https://doi.org/10.1093/sleep /6.1.16
- Stoberl, A. S., Schwarz, E. I., Haile, S. R., Turnbull, C. D., Rossi, V. A., Stradling, J. R., & Kohler, M. (2017). Night-to-night variability of obstructive sleep apnea. Journal of Sleep Research, 26(6), 782–788. https://doi.org/10.1111/jsr.12558
- Stradling, J. R., & Davies, R. J. (2004). Sleep. 1: Obstructive sleep apnoea/hypopnoea syndrome: Definitions, epidemiology, and natural history. Thorax, 59(1), 73–78. https://doi.org/10.1136/thx.2003.007161
- Tkacova, R., McNicholas, W. T., Javorsky, M., Fietze, I., Sliwinski, P., Parati, G., …, European Sleep Apnoea Database Study, (2014). Nocturnal intermittent hypoxia predicts prevalent hypertension in the European Sleep Apnoea Database cohort study. European Respiratory Journal, 44(4), 931–941. https://doi.org/10.1183/09031 936.00225113
- Ueno, K., Kasai, T., Brewer, G., Takaya, H., Maeno, K.-I., Kasagi, S., … Narui, K. (2010). Evaluation of the apnea-hypopnea index determined by the S8 auto-CPAP, a continuous positive airway pressure device, in patients with obstructive sleep apnea-hypopnea syndrome. Journal of Clinical Sleep Medicine, 6(2), 146–151. https://doi. org/10.5664/jcsm.27763
- Vat, S., Haba-Rubio, J., Tafti, M., Tobback, N., Andries, D., & Heinzer, R. (2015). Scoring criteria for portable monitor recordings: A comparison of four hypopnoea definitions in a population-based cohort. Thorax, 70(11), 1047–1053. https://doi.org/10.1136/thora xjnl-2014-205982
- Weimin, L., Rongguang, W., Dongyan, H., Xiaoli, L., Wei, J., & Shiming, Y. (2013). Assessment of a portable monitoring device WatchPAT 200 in the diagnosis of obstructive sleep apnea. European Archives of Oto-Rhino-Laryngology, 270(12), 3099–3105. https://doi.org/10.1007/s0040 5-013-2555-4
- Wimms, A. J., Kelly, J. L., Turnbull, C. D., McMillan, A., Craig, S. E., O'Reilly, J. F., … Morrell, M. J. (2020). Continuous positive airway pressure versus standard care for the treatment of people with mild obstructive sleep apnoea (MERGE): A multicentre, randomised controlled trial. The Lancet Respiratory Medicine, 8(4), 349–358. https://doi.org/10.1016/S2213 -2600(19)30402 -3
- Won, C. H. J., Qin, L., Selim, B., & Yaggi, H. K. (2018). Varying hypopnea definitions affect obstructive sleep apnea severity classification and association with cardiovascular disease. Journal of Clinical Sleep Medicine, 14(12), 1987–1994. https://doi.org/10.5664/jcsm.7520
- Ye, L., Pien, G. W., Ratcliffe, S. J., Björnsdottir, E., Arnardottir, E. S., Pack, A. I., … Gislason, T. (2014). The different clinical faces of obstructive sleep apnoea: A cluster analysis. European Respiratory Journal, 44(6), 1600–1607. https://doi.org/10.1183/09031 936.00032314
- Young, T., Palta, M., Dempsey, J., Skatrud, J., Weber, S., & Badr, S. (1993). The occurrence of sleep-disordered breathing among middle-aged adults. New England Journal of Medicine, 328(17), 1230–1235. https://doi.org/10.1056/NEJM1 99304 29328 1704
- Young, T., Peppard, P., Palta, M., Hla, K. M., Finn, L., Morgan, B., & Skatrud, J. (1997). Population-based study of sleep-disordered breathing as a risk factor for hypertension. Archives of Internal Medicine, 157(15), 1746–1752.
- Yu, J., Zhou, Z., McEvoy, R. D., Anderson, C. S., Rodgers, A., Perkovic, V., & Neal, B. (2017). Association of positive airway pressure with cardiovascular events and death in adults with sleep apnea: A systematic review and meta-analysis. JAMA, 318(2), 156–166. https://doi.org/10.1001/jama.2017.7967
- Zarhin, D. (2015). Contesting medicalisation, doubting the diagnosis: Patients' ambivalence towards the diagnosis of Obstructive Sleep Apnoea. Sociology of Health & Illness, 37(5), 715–730. https://doi.org/10.1111/1467-9566.12229