Weak clinical effect of airway clearance on ADH and BNP concentration: mechanism or data collection BIAS

To the editor,

Nocturnal enuresis is a disorder characterized by intermittent urinary incontinence that occurs during periods of sleep for at least one episode per month for at least 3 months (¹). These episodes occur at a time when the child should, under normal circumstances, be able to control urination. In addition, although some causes are more common, such as lack of pelvic floor muscle control (²) and the presence of psychiatric disorders (³), there are also pathophysiological factors that can lead to the onset of nocturnal enuresis, such as obstruction of the upper airways (⁴).

This pathophysiological picture is captured by sympathetic receptors of the Autonomic Nervous System, which cause greater cardiomyocyte activity, secreting B-type natriuretic peptide (BNP) by the ventricles, which stimulates natriuresis and diuresis in order to compensate for the vasoconstrictor systems. that are activated in these situations. This increase in BNP, due to the pathophysiological condition of OSA, causes inhibition of the secretion of antidiuretic hormone (ADH), which regulates diuresis through the reabsorption of water in the collecting ducts (⁴).

The study by Ribeiro et al. (⁵), published in this journal in issue 48 (⁶), presents interesting results on enuresis. However, we bring an analysis based on clinical effect measurement to complement the probabilistic analysis presented by the authors. The measure of the clinical effect used is the Cohen's d, whose meaning is used to find out the usefulness of the probabilistic effect, which is influenced by the sample size and selection method (⁶).

The improvement shown for nocturnal enuresis in the study by Ribeiro et al. (⁵) was clinically very large (d=1.50) compared to the effects of surgery on the concentration of ADH (d=0.38) and BNP (d=0, 32), which are considered small clinical effects, even the comparison before and after BNP being significant from the probabilistic point of view.

From this, due to the paradoxical effect of ADH and BNP, some considerations of the mechanism of effect of upper airway obstruction on nocturnal enuresis in children arise: the small clinical effect of the increase in BNP is enough to strongly increase the proportion of nights dry? Can the delay time in data collection between 90 and 120 days affect hormonal indicators mainly in the heterogeneity of the sample? Is there another factor involved?

Therefore, we can conclude that airway clearance modifications had little clinical impact on the hormonal actions of ADH and BNP as collected.

The Authors

Table 1
Measures of the clinical effect of upper airway clearance on enuresis and BNP and ADH hormones.

	Xbefore	Xafter	SDbefore	SDafter	Xbefore-Xafter	SDm	N	Square SD	Cohen's d
BNP (pg/mL)	116.5	156.2	126.5	112.3	-39.7	716291.05	49	120.90	-0.32
Dry nights %	32.3	75.4	24.7	33.4	-43.1	40003.81	49	28.57	-1.50
ADH (pg/mL)	5.8	14.6	3.2	35.4	-8.8	25360.16	49	22.74	-0.38

• ADH = anti-diuretic hormone; BNP = brain natriuretic peptide; X = Mean; SD = Standard deviation; N = sample number.

REFERENCES

• ¹
  Koff SA, Jayanthi VR. Non-neurogenic lower urinary tract dysfunction. In: Walsh PC, Retik AB, Vaughan ED Jr, Wein AJ, Kavoussi LR, Novick AC. eds. Campbell's urology. Philadelphia: Saunders;2002; p.2262-83.
• ²
  Campos RM, Lúcio AC, Lopes MH, Hacad CR, Perissinotto MC, Glazer HI†, et al. Exercícios dos músculos do assoalho pélvico exclusivos ou em combinação com oxibutinina no tratamento da enurese não monossintomática. Um estudo randomizado controlado com 2 anos de seguimento. Einstein (São Paulo). 2019;17(3):eAO4602.
• ³
  Hjalmas K, Arnold T, Bower W, Caione P, Chiozza LM, von Gontard A, et al. Nocturnal enuresis: an international evidence based management strategy. J Urol. 2004;171(6 Pt 2):2545-61.
• ⁴
  Bastos JM Netto, Rondon AV, de Lima GRM, Zerati M Filho, Schneider-Monteiro ED, Molina CAF, et al. Brazilian consensus in enuresis-recomendations for clinical practice. Int Braz J Urol. 2019;45:889-900.
• ⁵
  Ribeiro A, Bastos JM Netto, de Figueiredo AA, Cândido TC, Guércio WB, Zica BO. Enuresis and upper airway obstruction: BNP and ADH hormones behavior before and after airway surgery. Int Braz J Urol. 2022;48:937-43.
• ⁶
  Lakens D. Calculating and reporting effect sizes to facilitate cumulative science: a practical primer for t-tests and ANOVAs. Front Psychol. 2013;4:863.

Publication Dates

• Publication in this collection
  14 Aug 2023
• Date of issue
  Jul-Aug 2023

History

• Received
  31 Mar 2023
• Accepted
  26 Apr 2023
• Published
  20 May 2023