An analysis of the degree of concordance among international guidelines regarding alpha-1 antitrypsin deficiency

Abstract

Background: Practice guidelines (PGs) attempt to standardize practice to optimize care. For uncommon lung diseases like alpha-1 antitrypsin deficiency (AATD), a paucity of definitive studies and geographic variation in prevalence may hamper guideline generation. The current study assembled and assesses the degree of concordance among available PGs regarding AATD.

Methods: To assess concordance, 15 eligible guidelines focused on AATD were evaluated regarding recommendations surrounding 24 key clinical issues. A Delphi process achieved consensus on ratings for each statement among 3 reviewers. Agreement was quantified as the proportion of guideline comparisons with a matching rating.

Results: The overall level of agreement was 47% (1190/2520 comparisons). The overall "affirmative agreement percentage" (ie, when guidelines agreed in endorsing a practice), was 42% (501/1190 comparisons). The agreement for individual clinical statements ranged from 26% to 75%. A broad consensus was seen in the recommendation to test all patients with a history of fixed obstruction on pulmonary function testing (either from asthma or COPD). Given that AATD is an under-recognized disease and that diagnosis often occurs at a late stage, the authors are encouraged by this consensus. Where overall the guidelines were less explicit was when to refer to a specialist or AATD center. Deciding on a treatment strategy requires a thorough understanding of the alpha 1 serum level, genotype, pulmonary function testing, and imaging, and therefore the authors feel that all patients would benefit from a specialty referral if the diagnosis of AATD is being considered.

Conclusion: Available guidelines regarding AATD frequently disagreed in management recommendations. Possible explanations for discordance include differences in regional prevalence, availability of augmentation therapy, and insurance environments. Attempts to harmonize the various guidelines by empaneling a broadly representative international group of disease experts should be considered for AATD. Similar comparisons among guidelines for other diseases are recommended.

Keywords: alpha-1 antitrypsin deficiency; chronic obstructive pulmonary disease; clinical management; practice guidelines.

Figure 1

PRISMA flow diagram. Medline and Embase were searched using search terms “alpha-1 antitrypsin deficiency,” “COPD,” and “guidelines.” Eligible guidelines were published in English and were issued by official respiratory organizations/medical societies and/or by national organizations.

Figure 2

Affirmative agreement among guidelines on individual clinical statements. For each clinical statement, the affirmative proportions of guideline comparisons endorsing an action (with or without an added condition, Y + YC) are plotted. Negative agreements are also plotted. The highest affirmative agreement percentage was for the statement: “Initial testing should include a serum AAT level” (74%). The highest negative agreement percentage was for the statement: “Only patients with suggestive features of AAT deficiency should be tested” (43%). Abbreviations: Y, yes; YC, yes, conditional; AAT, alpha-1 antitrypsin.