Referral to Asthma Diagnostic Consultation Services Improves Diagnosis, Treatment

Researchers at Maastricht University Medical Center in The Netherlands recently found that general practitioner (GP) referrals to an asthma diagnostic consultation service (ADCS) substantially improved the accuracy of their patients’ asthma diagnoses.¹

Asthma is often under- or overdiagnosed, partially due to inaccurate diagnosis by primary healthcare providers. Overdiagnosis can result in unnecessary treatment, side effects, and higher costs , while underdiagnosis can lead to worse outcomes and increased mortality.^2-5 In one study, approximately 30% of patients with respiratory symptoms were using inhaled corticosteroids with no clear indication, and it was determined that more than 10% of these individuals did not need the drugs.³

In The Netherlands, GPs use a national guideline to facilitate asthma diagnosis, which ideally includes confirmatory spirometry. However, stable asthma patients often have a normal spirometry result, and chronic asthma patients may not respond to bronchodilatory medication, thus clouding the diagnostic picture. “So, in terms of diagnostics these two categories of asthma patients will pose diagnostic problems for GPs, despite their detailed guideline description,” the researchers wrote.

In the new study published in NPJ Primary Care Respiratory Medicine researchers examined the effects of implementing an ADCS for GPs at a hospital in The Netherlands. Visits provided by the service included a physical examination, medical history review, and histamine challenge test. A main goal of the investigation was to determine the level of congruence between the ADCS diagnosis and the GP’s working hypotheses, as well as any consequences on patients’ pharmacotherapy. The sample included 659 patients older than 12 years of age (mean age, 45.3 years; 60% female).

Four years of observation revealed that asthma diagnosis was excluded in 52% of patients referred to the ADCS by their GP, and the diagnosis was confirmed in 42% of referred patients. In addition, while GPs diagnosed 25% of patients with chronic rhinitis, the prevalence was 40% when diagnosed by the ADCS. Diagnostic adjustments by the ADCS led to a medication change in 74% of patients overall; 10% of patients started a medication due to a new asthma diagnosis; and 12% stopped a respiratory medication after their diagnosis was corrected. Of the patients referred to the ADCS, 91% were referred back to their GP, and 6% remained under the care of the ADCS due to severe unstable asthma.

These results demonstrated that the ADCS significantly helped GPs in “setting accurate diagnoses for their patients with an asthma hypothesis” the investigators concluded. ADCS may reduce the incidence of over- and underdiagnosing patients and result in more appropriate treatments.

Summary and Clinical Applicability

When GPs referred patients to an ADCS, diagnostic accuracy and appropriateness of patients’ pharmacotherapy improved.

References

1. Gillis RME, van Litsenburg W, van Balkom RH, Muris JW, Smeenk FW. The contribution of an asthma diagnostic consultation service in obtaining an accurate asthma diagnosis for primary care patients: results of a real-life study. NPJ Prim Care Respir Med. 2017;27(1):35. doi:10.1038/s41533-017-0027-9.
2. Lucas A, Smeenk F, Smeele I, Brouwer T, van Schayck OP. The validity of diagnostic support of an asthma/COPD service in primary care. Br J Gen Pract. 2007;57(544):892-896. doi:10.3399/096016407782317883
3. Lucas AE, Smeenk FW, Smeele IJ, van Schayck OP. Overtreatment with inhaled corticosteroids and diagnostic problems in primary care patients, an exploratory study. Fam Pract. 2008;25(2):86-91. doi:10.1093/fampra/cmn006
4. Lucas AE, Smeenk FW, Smeele IJ, van Schayck OP. Diagnostic accuracy of primary care asthma/COPD working hypotheses, a real-life study. Respir Med. 2012;106(8):1158-1163. doi:10.1016/j.rmed.2012.03.002
5. Bethesda M. National Asthma Education and Prevention Program: Expert panel report III: guidelines for the diagnosis and management of asthma. National Heart, Lung, and Blood Institute; 2007. Report No.: NIH publication no. 08-4051.  https://www.ncbi.nlm.nih.gov/books/NBK7232/. Accessed July 28, 2017.