Refractory chronic cough due to gastroesophageal reflux: Definition, mechanism and management

Positive effect of deep diaphragmatic breathing training on gastroesophageal reflux-induced chronic cough: a clinical randomized controlled study

BACKGROUND AND OBJECTIVE

To explore the efficacy of deep diaphragmatic breathing training (DEP) in patients with gastroesophageal reflux-induced chronic cough (GERC).

METHODS

A randomized controlled study was conducted involving 60 GERC patients who were divided into the intervention group and the control group (each with 30 patients). Both groups received routine medication treatment for GERC, while the intervention group received DEP training additionally. Both groups were evaluated by cough symptom scores, Hull airway reflux questionnaire (HARQ), gastroesophageal reflux diagnostic questionnaire (GerdQ), generalized anxiety disorder scale-7 (GAD-7), patient health questionnaire-9 (PHQ-9), Pittsburgh sleep quality index (PSQI), the Leicester cough questionnaire (LCQ), as well as capsaicin cough sensitivity testing, B-ultrasound and surface electromyography (sEMG) of the diaphragmatic muscles before and after treatment. The cough resolution rate and changes of the above indictors was compared between the two groups after eight weeks of treatment.

RESULTS

After eight weeks of treatment, cough symptoms improved in both groups, but the cough resolution rate in the intervention group of 94% was significantly higher than that in the control group of 77% (χ2 = 6.402, P = 0.041). The intervention group showed significant improvements to the control group in GerdQ (6.13(0.35) VS 6.57(0.77)), GAD-7 (0(0;1) VS 1(0;3)), PSQI (2(1;3) VS 4(3;6)), LCQ (17.19(1.56) VS 15.88(1.92)) and PHQ-9 (0(0;0) VS 0(0;3)) after treatment. Compared to control group, sEMG activity of the diaphragmatic muscle was significantly increased in the intervention group after treatment, measured during DEP (79.00(2.49) VS 74.65 (1.93)) and quiet breathing (72.73 (1.96) VS 67.15 (2.48)).

CONCLUSION

DEP training can improve cough symptoms as an adjunctive treatment in GERC patients.

TRIAL REGISTRATION

The protocol was registered in February 2, 2022 via the Chinese Clinical Trials Register ( http://www.chictr.org.cn/ ) [ChiCTR2200056246].

Profile of cough triggers and their relationship with capsaicin cough sensitivity in chronic cough

BACKGROUND

Cough hypersensitivity is an important part of the neurophysiology of cough, which presents with increased cough response to a lower level of stimuli or triggers. Classification of stimuli might bring about additional insight into the underlying mechanisms and management.

OBJECTIVES

This study investigated the profile of cough triggers in chronic cough patients and their relationship with capsaicin cough sensitivity.

DESIGN

This was a cross-sectional observational study.

METHODS

We enrolled patients with different causes of chronic cough from 2006 to 2021. Cough triggers were defined as cough response to chemical triggers, mechanical triggers, meal triggers, or thermal trigger. Cough sensitivity to capsaicin was evaluated by the capsaicin challenge test, which was expressed as the lowest concentration of capsaicin inducing 5 or more coughing (C5).

RESULTS

Among 1211 patients with chronic cough, 1107 (91.4%) patients reported at least one cough trigger. Chemical triggers (66.9%) were the most common cough triggers, followed by thermal exposure (50.6%), mechanical triggers (48.2%), and meal triggers (21.2%). There was no difference in the proportion of chemical triggers among different etiologies. Patients with refractory chronic cough reported the highest prevalence of cough triggers (97.1%). A higher number of meal triggers (34.9%) was associated with gastroesophageal reflux-related cough, and meal triggers and mechanical triggers were more common in refractory chronic cough. Among 254 patients who completed capsaicin challenge test, both the number of total triggers and the number of chemical triggers had a significant but mild correlation with capsaicin cough sensitivity.

CONCLUSION

Cough hypersensitivity as reflected by a variety of cough triggers is a common feature in chronic cough patients, but different etiologies present specific profiles of cough triggers, which could not be evaluated comprehensively by capsaicin cough sensitivity.

New Insights Into Refractory Chronic Cough and Unexplained Chronic Cough: A 6-Year Ambispective Cohort Study

PURPOSE

Only limited studies have depicted the unique features and management of refractory chronic cough (RCC) and unexplained chronic cough (UCC). These led to the initiation of this study, which reported the demographic characteristics, manifestations, and long-term outcomes on a large series of consecutive RCC/UCC patients, providing a guideline-led real-world clinical experience.

METHODS

Retrospective baseline information was obtained from Clinical Research Database (January 2016 to May 2021). At least 6 months after the last clinic visit, included subjects were prospectively followed up.

RESULTS

Three hundred and sixty-nine RCC and UCC patients (199 females, 53.9%) were analyzed. The median cough duration was 24.0 (12.0-72.0) months. Laryngeal symptoms were reported in 95.9% of the patients. The common triggers for coughing were talking (74.9%), pungent odors (47.3%), eating (45.5%), and cold air (42.8%). RCC was considered in 38.2%, and the remainder of 228 patients had UCC, with an equal sex distribution (P = 0.66). Among the 141 RCCs, 90.8% (128) had refractory reflux cough, which was more responsive to current treatments (P < 0.01). Although most features and test results between RCC and UCC were similar, UCC was more commonly inappropriately treated (P < 0.01). Nineteen (7.7-41.1) months after the final clinic visit, 31.2% still coughed persistently, while 68.8% reported cough improvement or remission. RCC reported more favorable treatment outcomes (including cough improvement, control, and spontaneous remission) than UCC (P < 0.01). Coughs with long duration before the initial cough clinic visit (P < 0.01), frequent urinary incontinence (P < 0.01), and being sensitive to "talking" (P < 0.01) or "cold air" (P < 0.01) were less likely to be solved.

CONCLUSIONS

The current treatments only improve cough symptoms in two-thirds of patients. Clinical indicators for treatment failure were those coughing for long duration and being sensitive to "talking" or "cold air."

Pathogenesis and management of gastroesophageal reflux disease-associated cough: a narrative review

Background and Objective

Gastroesophageal reflux disease (GERD)-associated cough is defined as a special GERD with a predominant cough symptom and is a common cause of chronic cough. This review summarizes our current understanding on the pathogenesis and management of GERD-associated cough.

Methods

Main literatures on the pathogenesis and management of GERD-associated cough were reviewed and our understandings derived from the published studies were showed then.

Key Content and Findings

Although esophageal-tracheobronchial reflex mainly underlies the pathogenesis of GERD-associated cough, its counterpart-tracheobronchial-esophageal reflex might exist and initiate the cough due to reflux induced by upper respiratory tract infection through the signaling of transient receptor potential vanilloid 1 linking airway and esophagus. The presence of reflux-associated symptoms such as regurgitation and heartburn along with coughing suggests an association between cough and GERD, which is supported by the objective evidence of abnormal reflux as detected by reflux monitoring. Although there is no general consensus, esophageal reflux monitoring provides the main diagnostic criteria for GERD-associated cough. Despite that acid exposure time and symptom associated probability are useful and mostly employed reflux diagnostic criteria, they are imperfect and far from being the gold standard. Acid suppressive therapy has long been recommended as the first choice for GERD-associated cough. However, the overall benefits of proton pump inhibitors have been controversial and need to be further assessed, especially in patients with cough due to non-acid reflux. Neuromodulators have demonstrated potential therapeutic effects for refractory GERD-associated cough, for which anti-reflux surgery may also be a promising treatment option.

Conclusions

Tracheobronchial-esophageal reflex might initiate reflux-induced cough provoked by the upper respiratory tract infection. It is necessary to optimize the current standards and to explore new criteria with higher diagnostic potency. Acid suppressive therapy is the first choice for GERD-associated cough, followed by neuromodulators and anti-reflux surgery for refractory GERD-associated cough.

GERD-related chronic cough: Possible mechanism, diagnosis and treatment

GERD, or gastroesophageal reflux disease, is a prevalent medical condition that affects millions of individuals throughout the world. Chronic cough is often caused by GERD, and chronic cough caused by GER is defined as GERD-related chronic cough (GERC). It is still unclear what the underlying molecular mechanism behind GERC is. Reflux theory, reflex theory, airway allergies, and the novel mechanism of esophageal motility disorders are all assumed to be linked to GERC. Multichannel intraluminal impedance combined with pH monitoring remains the gold standard for the diagnosis of GERC, but is not well tolerated by patients due to its invasive nature. Recent discoveries of new impedance markers and new techniques (mucosal impedance testing, salivary pepsin, real-time MRI and narrow band imaging) show promises in the diagnosis of GERD, but the role in GERC needs further investigation. Advances in pharmacological treatment include potassium-competitive acid blockers and neuromodulators (such as Baclofen and Gabapentin), prokinetics and herbal medicines, as well as non-pharmacological treatments (such as lifestyle changes and respiratory exercises). More options have been provided for the treatment of GERC other than acid suppression therapy and anti-reflux surgery. In this review, we attempt to review recent advances in GERC mechanism, diagnosis, and subsequent treatment options, so as to provide guidance for management of GERC.

Limited Clinical Utility of Lipid-Laden Macrophage Index of Induced Sputum in Predicting Gastroesophageal Reflux-Related Cough

Gastroesophageal reflux disease (GERD) is a common cause of chronic cough (CC). However, the diagnosis of GERD associated with CC based on 24-hour esophageal pH-monitoring or favorable response to empirical anti-reflux trials is invasive and time-consuming. Lipid-laden macrophages (LLMs) are supposed to be a biomarker for micro-aspiration of gastric content in the respiratory tract. This study was conducted to collect LLMs by the sputum induction technique and observe the relationship among the amount of LLMs, cough severity, parameters of 24-hour esophageal pH-monitoring and therapeutic response. The 24-hour esophageal pH-monitoring and sputum induction were performed on 57 patients with suspected GERD associated with CC. Thirty-four patients were followed up after empirical anti-reflux trials of 8 weeks to record the therapeutic response. Lipid-laden macrophage index (LLMI), a semiquantitative counting of LLMs, showed no significant correlation with the values of 24-hour esophageal pH monitoring at the proximal or remote electrode. No difference in LLMI or DeMeester score, as well as cough symptom association probability, were found between the responders and the non-responders. Reflux symptoms were more common in the responders (50%) compared to the non-responders (6%) (P < 0.05). Our study suggests that LLMI shows limited utility in clinically diagnosing GERD associated with CC as an underlying etiology or in predicting response to anti-reflux therapy. Anti-reflux therapy is more effective for CC patients with reflux symptoms than for those without.

Pressure and length of the lower esophageal sphincter as predictive indicators of therapeutic efficacy of baclofen for refractory gastroesophageal reflux-induced chronic cough

BACKGROUND

Therapeutic efficacy of baclofen is suboptimal in the treatment of refractory gastroesophageal reflux-induced chronic cough (GERC). The purpose of the study is to identify its therapeutic predictors in a prospective clinical study.

METHODS

138 patients with suspected refractory GERC were treated with baclofen. Before the therapy, all the patients underwent esophageal manometry and multichannel intraluminal impedance-pH monitoring to establish the diagnosis. After the efficacy of baclofen was evaluated, a stepwise logistic regression analysis was performed to identify the therapeutic predictors of baclofen and to establish a regression prediction model.

RESULTS

The overall response rate of baclofen treatment was 52.2% (72/138). The lower esophageal sphincter pressure (LESP) (odds ratio (OR) = 0.592, P = 0.000) and lower esophageal sphincter length (LESL) (OR = 0.144, P = 0.008) were independent predictors of baclofen efficacy. The optimal cut-off point to predict baclofen efficacy for LESP was 11.00 mmHg, with a sensitivity of 83.7% and specificity of 79.1% while that for LESL was 2.35 cm, with a sensitivity of 81.6% and specificity of 72.1%. The highest predictive specificity (90.7%) was achieved when both LESP and LESL were jointly used.

CONCLUSIONS

LESP and LESL may be used to screen the patients with refractory GERC suitable for baclofen therapy and help improve the therapeutic precision.

CLINICAL TRIAL REGISTRATION

ChiCTR- ONC-13003123.

Prediction of therapeutic efficacy of gabapentin by Hull Airway Reflux Questionnaire in chronic refractory cough

Background:

Gabapentin is recommended for the treatment of chronic refractory cough (CRC). This study aims to identify its therapeutic predictors in a prospective clinical study.

Methods:

A total of 179 patients with CRC were treated with gabapentin. Prior to the therapy, all patients were assessed by Hull Airway Reflux Questionnaire (HARQ) and inhaled capsaicin challenge. When the treatment ended and cough resolution was confirmed, a stepwise logistic regression analysis was performed to identify the therapeutic predictors for gabapentin and to establish the prediction equation.

Results:

Gabapentin treatment achieved a therapeutic success rate of 66.48%. HARQ scores were significantly higher in responders than non-responders to gabapentin (29.79 ± 9.58 versus 21.95 ± 7.83, t = –3.685, p <0.001), which were positively related to the therapeutic efficacy of gabapentin (r = 0.433, p <0.001). The optimal cutoff point of 21.50 in HARQ presented with a moderate ability to predict gabapentin efficacy, with a sensitivity of 84.60% and specificity of 63.60%. Multiple logistic regression identified items of “A tickle in your throat, or a lump in your throat” (OR = 7.927, p = 0.005), “Cough when you get out of bed in the morning” (OR = 7.016, p = 0.045), and “Cough with eating” (OR = 6.689, p = 0.011) as independent predictors. The established logistic regression equation predicted 83.72% of the treatment success rate of gabapentin, which was verified by consequent preliminary revalidating study in 59 patients.

Conclusion:

HARQ may be useful to screen patients with CRC most likely responsive to gabapentin, and help improve the therapeutic success.

Trial registration:

http://www.chictr.org/; No.: ChiCTR-ONC-13003123

Gabapentin versus baclofen for treatment of refractory gastroesophageal reflux-induced chronic cough

Refractory gastroesophageal reflux-induced chronic cough (GERC) is a special type of gastroesophageal reflux disease (GERD) with predominant cough resistant to pragmatic standard anti-reflux therapy including antisecretory agents alone or in combination with promotility agents but with a favorable response to intensified anti-reflux treatment. The condition is not rare and is difficult to treat. Neuromodulators such as baclofen and gabapentin are considered potential therapeutic options for refractory GERC. Limited data indicate that gabapentin and baclofen could attenuate the cough symptom in patients with refractory GERC by blockade of gastroesophageal reflux or by direct antitussive effects. However, no study has compared the efficacy of these two drugs in treatment of refractory GERC. In an open-labeled randomized clinical study, we demonstrated that, as add-on therapy, gabapentin and baclofen had a similar prevalence of therapeutic success for suspected refractory GERC but gabapentin may be more preferable because of its fewer central side effects. The efficacy of baclofen and gabapentin was suboptimal, so further studies are needed to select the patients with refractory GERC suitable for precise treatment using these two neuromodulators.

Proximal reflux: biochemical mediators, markers, therapeutic targets, and clinical correlations

Airway reflux is implicated in the pathophysiology of a wide range of adult and pediatric upper and lower airway diseases. However, the diagnosis of proximal reflux-associated disease remains challenging due to evolving clinical criteria and institutional and regional variances in diagnostic practices. Evidence suggests that nonacidic contents of reflux may serve as both pathologic mediators of and biomarkers for reflux in the upper airway. Furthermore, they offer potential pharmaceutical and surgical intervention targets and are the focus of novel clinical diagnostic tools currently under investigation.

Gastroesophageal Reflux Disease: Pathophysiology, Diagnosis, and Treatment

Gastroesophageal reflux disease (GERD) is a common chronic disorder in industrialized countries. Gastroesophageal reflux disease is one of the most frequent diseases encountered by primary care providers. The primary symptoms of GERD include heartburn, regurgitation, globus sensation, dysphagia, chest pain, and belching. If symptoms are left untreated, a major concern is complications and the potential risk of esophageal adenocarcinoma associated with GERD. With the increasing prevalence and incidence of GERD and the increasing cost of this disease, there is a need for advanced practice registered nurses to understand the nature of GERD including its pathophysiology, signs and symptoms, and treatment options to address the disease.

Esophageal Impedance-pH Monitoring and Pharyngeal pH Monitoring in the Diagnosis of Extraesophageal Reflux in Children

Various clinical symptoms are attributed to extraesophageal reflux disease (EERD). Multichannel intraluminal impedance-pH monitoring (MII-pH) is considered to correlate symptoms with acid and nonacid gastroesophageal reflux (GER) events. Pharyngeal pH monitoring (Dx-pH) is considered to correlate the decrease in the pH level in the oropharynx with reported symptoms and to diagnose supraesophageal reflux. We aimed to assess the correlation between acid reflux episodes recorded by Dx-pH and GER detected via MII-pH in children with suspected EERD. The study enrolled 23 consecutive children (15 boys and 8 girls; median age 8.25 [range 3-16.5] years) with suspected EERD. MII-pH and Dx-pH were conducted concurrently in all patients. A total of 1228 reflux episodes were recorded by MII-pH. With the antimonic sensor placed inside the impedance probe, 1272 pH-only reflux episodes were recorded. Of these, 977 (76.81%) were associated with a retrograde bolus transit. Regarding GER, 630 full-column episodes extended to the most proximal pair of impedance sensors; 500 (83.33%) demonstrated an acidic character. The following acid reflux numbers were determined by the Dx-pH system: for pH < 4, n = 126; pH < 4.5, n = 136; pH < 5, n = 167; and pH < 5.5, n = 304, and for a decrease in pH > 10% relative to the baseline, n = 324. There was no significant correlation between the number of pharyngeal reflux episodes detected by Dx-pH and that of GERs identified by MII-pH. The proportion of oropharyngeal pH events that were temporally related to a GER episode increased with the extended pH criteria. The highest proportion was observed for a pH decrease of ≥10% from the baseline and did not exceed 5.2%. The application of the extended pH criteria in the Dx-pH system resulted in an increase in the number of diagnosed laryngopharyngeal refluxes; most were not temporally associated with GER episodes confirmed by MII-pH. Thus, the efficacy of the exclusive application of Dx-pH for supraesophageal gastric reflux diagnosis is uncertain.

Randomised clinical trial: gabapentin vs baclofen in the treatment of suspected refractory gastro-oesophageal reflux-induced chronic cough

BACKGROUND

Neuromodulators are considered potential therapeutic options for refractory gastro-oesophageal reflux-induced chronic cough.

AIM

To compare the efficacy of gabapentin and baclofen in patients with suspected refractory gastro-oesophageal reflux-induced chronic cough.

METHODS

Two hundred and thirty-four patients with suspected refractory gastro-oesophageal reflux-induced chronic cough, who failed an 8-week course of omeprazole and domperidone, were recruited into the open-labelled study and randomly assigned to receive either gabapentin (maximum daily dose of 900 mg) or baclofen (maximum daily dose of 60 mg) for 8 weeks as add-on therapy to the previous treatment. The primary end point was the successful rate of cough resolution; and the secondary end-points included cough sensitivity to capsaicin and gastro-oesophageal reflux disease questionnaire score and reported side effects.

RESULTS

One hundred and eleven patients in the gabapentin group and 106 in the baclofen group completed the study. The overall success rate for cough resolution was comparable (57.3% vs 53.0%, χ²  = 0.357, P = 0.550) between the two groups. In parallel, cough sensitivity to capsaicin and gastro-oesophageal reflux disease questionnaire score decreased after treatment with either gabapentin or baclofen. However, gabapentin was associated with less frequent somnolence (20.5% vs 35.0%, χ²  = 6.156, P = 0.013) and dizziness (11.1% vs 23.9%, χ²  = 6.654, P = 0.010) than baclofen.

CONCLUSIONS

Gabapentin and baclofen have similar therapeutic efficacy for suspected refractory gastro-oesophageal reflux-induced chronic cough. However, gabapentin may be preferable because of fewer side effects. Trial Register: http://www.chictr.org/; No.: ChiCTR-ONC-13003066.

Etiology analysis of nonspecific chronic cough in children of 5 years and younger

This study aims to analyze the etiology of nonspecific chronic cough in children of 5 years and younger, in order to improve the diagnostic and treatment levels of pediatricians for nonspecific chronic cough in young children.The clinical data of 85 cases of children of 5 years old and below, who suffered from nonspecific chronic cough between the period of January 2015 and August 2016 were retrospectively analyzed.The etiology distribution of 85 cases of children with nonspecific chronic cough were as follows: 27 cases had cough variant asthma (31.8%), 32 cases had upper airway cough syndrome (37.6%), 16 cases had cough after infection (18.8%), 3 cases had gastroesophageal reflux cough (3.5%), 2 cases had allergic cough (2.4%), and 5 cases had unknown causes of cough (5.9%).The main composition ratio of the etiology of chronic cough in children of 5 years old and below is as follows (in sequence): upper airway cough syndrome, cough variant asthma, and post infection cough.

Evidence-Based Practice Guideline for Surgical Treatment of Gastroesophageal Reflux Disease 2018

The prevalence of gastroesophageal reflux disease (GERD) is increasing in Korea, and physicians, including surgeons, have been focusing on its treatment. Indeed, in Korea, medical treatment using a proton pump inhibitor is the mainstream treatment for GERD, while awareness of surgical treatment is limited. Accordingly, to promote the understanding of surgical treatment for GERD, the Korean Anti-Reflux Surgery Study Group published the Evidence-Based Practice Guideline for the Surgical Treatment of GERD. The guideline consists of 2 sections: fundamental information such as the definition, symptoms, and diagnostic tools of GERD and a recommendation statement about its surgical treatment. The recommendations presented 5 debates regarding fundoplication: 1) comparison of the effectiveness of medical and surgical treatments, 2) effectiveness of surgical treatment in cases of refractory GERD, 3) effectiveness of surgical treatment of extraesophageal symptoms, 4) comparison of effectiveness between total and partial fundoplication, and 5) effectiveness of fundoplication in cases of hiatal hernia. The present guideline is the first to demonstrate the efficacy of the surgical treatment GERD in Korea.

The efficacy of specific neuromodulators on human refractory chronic cough: a systematic review and meta-analysis

BACKGROUND

There have been several published reports on the use of orally administered, specific centrally acting medicines for the treatment of idiopathic cough; however, there is no extant systematic review of randomized controlled trials (RCTs) that evaluated their efficacy and safety for the treatment of idiopathic cough in human beings.

METHODS

We conducted a series of definitive systematic reviews and meta-analyses of RCTs. Claims data from the MEDLINE, EMBASE, LILACS, CBM, CNKI, VIP, Wan Fang, and Cochrane Library databases were used. We also reviewed articles and reference lists of relevant articles pertaining to human subjects published prior to March 26, 2016. No language restrictions were imposed. Two authors independently reviewed the titles and abstracts of the retrieved studies, which were matched using Review Manager 5.3 software. Disagreements were resolved by consensus. The outcome data were the number of subjects whose symptoms declined, measured by cough or Leicester Cough Questionnaire (LCQ) score. Random effect meta-analyses were used to pool the findings. Publication bias was assessed using funnel plots.

RESULTS

Three RCTs, regarding the medicines baclofen, amitriptyline, and gabapentin, were conducted involving 92 persons in total. Our reviews confirmed that baclofen, amitriptyline, and gabapentin show promise in the treatment of cough for select cases of refractory chronic cough. After-treatment relief of cough symptoms was significant (risk ratio =2.41; 95% CI: 1.15-5.04, n=84). Each of the medicines was well tolerated with minimal side effects. Methodological biases in the design and execution of cluster randomized trials might contribute to any selection bias in this review.

CONCLUSIONS

Baclofen, amitriptyline, and gabapentin may be effective 'non-specific' antitussives in clinical settings, although none of them are used in medical assessments or routinely included in the anatomic diagnostic protocol.

Evidence-based Evaluation and Management of Chronic Cough

Chronic cough is common and has a significant impact on the wellbeing of patients and the use and cost of health care services. Traditionally the approach to chronic cough in patients who are nonsmokers and are not taking an angiotensin-converting enzyme inhibitor has focused on the diagnosis and management of the upper airway cough syndrome, asthma, and reflux disease. The evaluation of patients with chronic cough frequently involves trials of empiric therapy for these 3 conditions. Chronic cough may be perpetuated by abnormalities of the cough reflex and sensitization of its afferent and central components.

A stepwise protocol for the treatment of refractory gastroesophageal reflux-induced chronic cough

BACKGROUND

Refractory gastroesophageal reflux-induced chronic cough (GERC) is difficult to manage. The purpose of the study is to evaluate the efficacy of a novel stepwise protocol for treating this condition.

METHODS

A total of 103 consecutive patients with suspected refractory reflux-induced chronic cough failing to a standard anti-reflux therapy were treated with a stepwise therapy. Treatment commences with high-dose omeprazole and, if necessary, is escalated to subsequent sequential treatment with ranitidine and finally baclofen. The primary end-point was overall cough resolution, and the secondary end-point was cough resolution after each treatment step.

RESULTS

High-dose omeprazole eliminated or improved cough in 28.1% of patients (n=29). Further stepwise of treatment with the addition of ranitide yielded a favorable response in an additional 12.6% (n=13) of patients, and subsequent escalation to baclofen provoked response in another 36.9% (n=38) of patients. Overall, this stepwise protocol was successful in 77.6% (n=80) of patients. The diurnal cough symptom score fell from 3 [1] to 1 [0] (Z=6.316, P=0.000), and the nocturnal cough symptom score decreased from 1 [1] to 0 [1] (Z=-4.511, P=0.000), with a corresponding reduction in the Gastroesophageal Reflux Diagnostic Questionnaire score from 8.6±1.7 to 6.8±0.7 (t=3.612, P=0.000). Conversely, the cough threshold C2 to capsaicin was increased from 0.49 (0.49) µmol/L to 1.95 (2.92) µmol/L (Z=-5.892, P=0.000), and the cough threshold C5 was increased from 1.95 (2.92) µmol/L to 7.8 (5.85) µmol/L (Z=-5.171, P=0.000).

CONCLUSIONS

Sequential stepwise anti-reflux therapy is a useful therapeutic strategy for refractory reflux-induced chronic cough.