Extrathoracic airway hyperresponsiveness as a mechanism of post infectious cough: case report

Efficacy and safety of Qing-Feng-Gan-Ke Granules in patients with postinfectious cough: study protocol of a novel-design phase III placebo-controlled, double-blind randomized trial

BACKGROUND

Postinfectious cough (PIC) is a common condition that affects millions of people worldwide every year. There is Western medicine for this condition but the treatment effect is often incomplete. Traditional Chinese medicine (TCM) has been increasingly prescribed for patients with PIC. Preliminary trials on Qing-Feng-Gan-Ke-Granules (QFGKG) conveyed promising results in treating PIC. This protocol describes an ongoing phase III randomized controlled clinical trial, designed according to a novel methodology of "one study, one primary outcome", with the objective of evaluating the efficacy and safety of QFGKG in patients suffering from PIC.

METHODS/DESIGN

This is a multicenter, phase III, randomized, double-blind, parallel-group, placebo-controlled clinical trial, comprising two simultaneously conducted study parts, part A and part B, intending to investigate two primary outcomes, i.e. time to cough resolution and cough symptom score, respectively. A total of 480 patients, aged 18 to 65 years, who complain of an ongoing persistent cough that has been lasting ≥ 3 weeks, will be recruited from six participating sites and then randomized to receive QFGKG 12.0 g twice daily or placebo 12.0 g twice daily. Each part will enroll 240 patients, with 180 patients being allocated to the QFGKG group and 60 to the placebo group.

DISCUSSION

Although traditional Chinese medicine is a structured intervention that has shown some promise in treating persistent cough, existing unconvincing evidence has noted limitations. This is a rare well-designed and rigorously-controlled, randomized, double-blind trial to evaluate the effects and safety of a Chinese herbal medicine in patients with postinfectious cough, providing tangible benefits for clinical research. Results of this trial are inclined to be conjectured as more truthful by implementing separate study parts that specifically estimate exclusive primary outcome. It will not only provide robust clinical evidence on the efficacy and safety of QFGKG for postinfectious cough, but will also provide a critical piece of information on the availability and superiority of a novel methodology for future clinical trials. The current trial is ongoing with recruitment of the predetermined number of patients being in progress.

TRIAL REGISTRATION

The two parts of this trial were separately registered with the Chinese Clinical Trial Registry: ChiCTR-TRC-13003278 (part A); and ChiCTR-TRC-13003337 (part B).

Honey plus coffee versus systemic steroid in the treatment of persistent post-infectious cough: a randomised controlled trial

BACKGROUND

Persistent post-infectious cough (PPC) is a cough that remains after a common cold or an upper respiratory tract infection for more than three weeks or perhaps for many months. Two of the suggested treatments for PPC are systemic steroid and honey plus coffee.

AIMS

The aim of this study was to evaluate and compare scientifically the therapeutic effects of these two regimens.

METHODS

A double-blind randomised controlled trial was conducted from 2008 to 2011 at the Baqiyatallah University Hospital, Tehran, Iran. Included in the study were 97 adults who had experienced PPC for more than three weeks. Patients with other causes of chronic cough, systemic disease, or abnormal routine laboratory tests were excluded. The participants were distributed into three groups. A jam like paste was prepared which consisted of honey plus coffee for the first group ('HC'), prednisolone for the second group (steroid, 'S'), and guaifenesin for the third group (control, 'C'). The participants were told to dissolve a specified amount of their product in warm water and to drink the solution every eight hours for one week. All the participants were evaluated before treatment and one week after completion of treatment to measure the severity of their cough. The main outcome measure was the mean cough frequency before and after one week's treatment calculated by a validated visual analogue cough questionnaire score.

RESULTS

There were 97 adult patients (55 men) enrolled in this study with the mean of age of 40.1 years. The mean (+/- SD) cough scores pre- and post-treatment were: HC group 2.9 (0.3) pre-treatment and 0.2 (0.5) post-treatment (p < 0.001); steroid ('S') group 3.0 (0.0) pre-treatment and 2.4 (0.6) post-treatment (p < 0.05); control ('C') group 2.8 (0.4) pre-treatment and 2.7 (0.5) post-treatment (p > 0.05). Analysis of variance showed a significant difference between the mean cough frequency before and after treatment in the HC group versus the S group (p< 0.001). Honey plus coffee was found to be the most effective treatment modality for PPC.

CONCLUSIONS

A combination of honey and coffee can be used as an alternative medicine in the treatment of PPC.

Gabapentin for refractory chronic cough: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Refractory chronic cough causes substantial symptoms and quality-of-life impairment. Similarities between central reflex sensitisation in refractory chronic cough and neuropathic pain suggest that neuromodulators such as gabapentin might be effective for refractory chronic cough. We established the efficacy of gabapentin in patients with refractory chronic cough.

METHODS

This randomised, double-blind, placebo-controlled trial was undertaken at an outpatient clinic in Australia. Adults with refractory chronic cough (>8 weeks' duration) without active respiratory disease or infection were randomly assigned to receive gabapentin (maximum tolerable daily dose of 1800 mg) or matching placebo for 10 weeks. Block randomisation was done with randomisation generator software, stratified by sex. Patients and investigators were masked to assigned treatment. The primary endpoint was change in cough-specific quality of life (Leicester cough questionnaire [LCQ] score) from baseline to 8 weeks of treatment, analysed by intention to treat. This study is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12608000248369.

FINDINGS

62 patients were randomly assigned to gabepentin (n=32) or placebo (n=30) and ten patients withdrew before the study end. Gabapentin significantly improved cough-specific quality of life compared with placebo (between-group difference in LCQ score during treatment period 1·80, 95% CI 0·56-3·04; p=0·004; number needed to treat of 3·58). Side-effects occurred in ten patients (31%) given gabapentin (the most common being nausea and fatigue) and three (10%) given placebo.

INTERPRETATION

The treatment of refractory chronic cough with gabapentin is both effective and well tolerated. These positive effects suggest that central reflex sensitisation is a relevant mechanism in refractory chronic cough.

FUNDING

National Health and Medical Research Council of Australia and Hunter Medical Research Institute, Newcastle, Australia.

Clinical and physiological features of postinfectious chronic cough associated with H1N1 infection

BACKGROUND

Post infectious chronic cough is a disabling illness. In 2009 an influenza pandemic occurred due to a novel strain of H1N1 influenza. Prolonged symptoms such as chronic cough remaining after the infection has cleared have not been examined. This study sought to investigate the prevalence, characteristics and mechanism of chronic cough following laboratory-confirmed H1N1 2009 influenza.

METHODS

Out of 836 eligible patients who had been tested by PCR assay for H1N1, 136 responders participated. Nineteen underwent detailed clinical investigation of cough, and airway function using symptom questionnaires, hypertonic saline challenge, and cough monitoring.

RESULTS

Post H1N1 chronic cough was reported by 43%, and chronic cough after non-H1N1 infection was present in 36% of participants. In the participants who progressed to testing objectively measured cough frequency was 3 times greater; there was a 9-fold increase in cough reflex sensitivity and greater quality of life impairment in the participants with postinfectious chronic cough following H1N1 infection than for the participants with no cough following H1N1 infection and for the healthy controls.

CONCLUSIONS

This study reports the first evaluation of chronic cough following H1N1 infection. Patients that develop chronic cough after H1N1 infection display increased cough reflex sensitivity up to 220 days after confirmed infection. There is an absence of associated risk factors and less impairment in quality of life compared to those patients normally seen in a specialist cough clinic. The associated mechanism was found to be cough reflex hypersensitivity.

TRIAL REGISTRATION

This clinical trial has been registered with the Australian New Zealand Clinical Trials Register, ACTRN12610000540011.

Speech pathology for chronic cough: a new approach

Chronic cough may persist despite systematic evaluation and medical treatment of known associated diseases such as asthma, rhinitis, and gastro-esophageal reflux. These patients have refractory chronic cough and many exhibit laryngeal hypersensitivity that is manifest at both a sensory and motor level. Examples of this are heightened sensitivity of the cough reflex to capsaicin, and laryngeal motor dysfunction with hoarse vocal quality and paradoxical vocal cord movement. Chronic cough that persists despite medical treatment may respond to speech pathology intervention. A multidimensional speech pathology treatment programme was designed based upon methods used to treat hyperfunctional voice disorders and paradoxical vocal fold movement. This included education, vocal hygiene training, cough suppression strategies and psychoeducational counseling. When tested in a single-blind, randomized, placebo-controlled trial involving 87 patients, participants in the treatment group demonstrated a significant reduction in cough, breathing, voice and upper airway symptoms following intervention, as well as improvements in auditory perceptual ratings of voice quality (breathy, rough, strain and glottal fry) and significant improvement in voice acoustic parameters (maximum phonation time, jitter and harmonic-to-noise ratio). Speech pathology intervention can be an effective way to treat refractory chronic cough.