DECAF score predicts acute COPD exacerbation mortality

Preventing COPD exacerbations has become an important goal in clinical management and a primary outcome in many COPD research trials. This is understandable – not only is the worsening of COPD distressing for patients but exacerbations can be severe enough to result in hospitalization and death. Unfortunately, as the health care dollar is stretched, more and more institutions are keeping hospital stays short or avoiding hospital stays altogther by using home care. This is safe only if we can identify low-risk patients or, put in reverse terms, identify the high risk patients. The British DECAF scores purports to do that. Patients with greater baseline breathlessness (D for dyspnea), low eosinophil counts (E for eosinopenia), chest x-rays showing pneumonia (C for consolidation), a blood gas showing acidic blood compatible with retaining CO2 (A for acidosis) and an irregular heartrate (F for atrial Fibrillation) are at high risk of death. To the specialist or hospitalist, none of this seems surprising but the quick mnemonic may be useful for the non-specialist doctor. Most of this is unsurprising but it’s worth highlighting that the single most useful predictive factor was baseline breathlessness prior to the exacerbation. Patients who were housebound by their breathlessness had a high mortality risk when they became ill with a worsening. A bit puzzling is the predictive value of a low eosinophil count. We usually associate this cell with allergic asthma. High eosinophil counts have been seen in the blood and sputum of patients with COPD have been reported, especially at times of exacerbation, and have suggested that asthma-like medicines may have a role (e.g. corticosteroids). A low count as a bad prognostic factor is intriguing. Does this mean a failure to mount an inflammatory response? Is there a confounding factor such as the inappropriate use of corticosteroids prior to exacerbation? Worth looking into. An interesting validation paper of the DECAF score can be found in Thorax, Open Access:

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