It was with great interest and attention that we read the letter sent by professors Lorenzi, Assis Viegas and Flávio Magalhães, which contains a series of important considerations regarding our recently published article "Extraesophageal manifestations of gastroesophageal reflux disease".(1) Notwithstanding the kind compliments regarding the clarity and quality of our text, which are very flattering, the essence of the correspondence is the limited amount of attention we seem to have given to obstructive sleep apnea syndrome (OSAS). There is a long-standing debate regarding the existence of a relationship between OSAS and gastroesophageal reflux disease (GERD). In 1989, Samelson(2) suggested that the negative intrathoracic pressure generated during OSAS could trigger gastroesophageal reflux episodes. Later, in the 1990s, various publications demonstrated that both OSAS and GERD improved with the use of nasal continuous positive airway pressure, supporting the hypothesis of a cause-and-effect relationship between these two pathologies. More recent studies have demonstrated that patients with OSAS are frequently affected by GERD. However, a cause-and-effect relationship between these two clinical situations has yet to be established. In 2002, Valipour et al.(3) used polysomnography and a specific validated questionnaire to evaluate 228 patients and yet were unable to establish a causal relationship between OSAS and GERD. Likewise, in 2004, Morse et al.(4) evaluated 136 patients, again using polysomnography and a validated questionnaire, and failed to obtain statistically significant results that would establish this relationship. Finally, in 2005, Kim et al.,(5) in a well conducted study involving the analysis of over 1000 patients, were not able to conclude that there was a definite relationship between OSAS and the presence or absence of GERD. One of the important aspects of that study was that a higher apnea-hypopnea index did not increase the probability that GERD would occur. The data available in the literature seem to indicate that concomitance between these two entities, which are both quite prevalent, might result from risk factors they have in common (obesity, for example), and it is unlikely that they result from a direct cause-and-effect situation. Evidently, the concomitance of OSAS and GERD is a fact of undeniable relevance. In light of this, we are grateful to the special attention given to the problem through the letter written by Professors Lorenzi, Viegas and Magalhães, who are known to be extremely knowledgeable and interested in this area, complementing our extensive review of a multidisciplinary topic of such amplitude as the extraesophageal manifestations of GERD. In conclusion, the fact that GERD is not associated with OSAS does not mean that the sleep-related pathologies should be underestimated. Considering its high prevalence and impact on patient quality of life, we should suspect its existence in routine medical practice, adopting appropriate practices for its diagnosis and employing procedures that are suited to its severity. Only then will we be able to recommend the most appropriate form of treatment for these complex problems that so significantly affect our patients.

REFERENCES

1. Gurski RR, Rosa ARP, Valle E, Borba MA, Valiatti AA. Manifestações extra-esofágicas da doença do refluxo gastroesofágico. J Bras Pneumol 2006;32(2)150-6
2. Samelson CF. Gastro-oesophageal reflux and obstructive sleep apnea. Sleep 1989;(21)12:475-6.
3. Valipour A, Makker HK, Hardy R, Emegbo S, Toma T, Spiro SG. Symptomatic gastro-oesophageal reflux in subjects with a breathing sleep disorder. Chest 2002; 121:(6)1748-53
4. Morse CA, Quan SF, Mays MZ, Green C, Stephen G, Fass R. Is there a relationship between obstructive sleep apnea and gastro-oesophageal reflux disease? Clin Gastroenterol Hepatol 2004;2:(9)761-8.
5. Kim HN, Vorona RD, Winn MP, Doviak M, Johnson DA, Ware JC. Symptoms of gastro-oesophageal reflux disease and the severity of obstructive sleep apnoea syndrome are not related in sleep disorders center patients. Aliment Pharmacol Ther 2005;21:1127-33.
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1. PhD from the Universidade Federal do Rio Grande do Sul (UFRGS, Federal University of Rio Grande do Sul); Postdoctoral work conducted at the University of Southern California (USC); Professor of the UFRGS Graduate Course in Surgery - Porto Alegre, Brazil
2. PhD in Surgery from the Universidade Federal do Rio Grande do Sul (UFRGS, Federal University of Rio Grande do Sul); Surgeon at the Porto Alegre Hospital de Clínicas - Porto Alegre, Brazil
3. Pulmonologist at the Hospital Moinhos de Vento - Porto Alegre, Brazil; Fellow of the American College of Chest Physicians, Northbrook, IL, USA
4. Student at the Universidade Federal do Rio Grande do Sul (UFRGS, Federal University of Rio Grande do Sul) - Porto Alegre, Brazil