Background Previous data has shown that premorbid MRC-dyspnoea (MRCD) score predicts outcomes following acute exacerbation of COPD (Steer, Thorax 2012). There are limited data on the clinical utility of the MRCD in predicting outcomes in patients requiring NIV to treat hypercapnic respiratory failure complicating an acute exacerbation.
Methods A single centre observational cohort study was undertaken from 1st April 2009 to 31st March 2012. We prospectively followed a cohort of patients admitted with acute exacerbation requiring NIV according to standard BTS criteria. Pre-admission MRCD were calculated from a prospective database obtained from the electronic patient record system as were hospital readmissions and mortality data.
Results 119 patients (69 male) with a mean age of 71 ± 12 years were admitted requiring NIV. Mean pH was 7.26 ± 0.07 with a PaCO2 9.47 ± 2.26 kPa and HCO3- of 30.6 ± 6.3 mmols/l. 102 patients (86%) survived the index hospital admission. 16 (16%) patients had previous admissions requiring acute NIV prior to April 2009. 63 (62%) survivors were readmitted or died within 1 year with 26 (25%) survivors having >1 readmission episode and 33 (32%) patients required NIV on readmission within a year. Median 1 year re-admission rate per patient was 1 (1–9) with median time to readmission 228 days for all patients and 373 days, 216 days, 105 days for MRC-dyspnoea score 2–3, 4 and 5, respectively. Median length of stay of the index admission was 9 days (1–48) with median length of readmission, or readmissions of 13 days (1–111). Hospital readmission accounted for 1251 bed days. There was significantly poorer 1 year survival in the most severely dyspnoeic patients (MRC 5) compared to the least (MRC 2 and 3) (HR 0.40, 95% CI 0.18–0.88, p = 0.023).
Conclusion These data show that COPD patients who receive acute NIV have high risk of hospital readmission including requirement for repeat NIV treatment, which contributed to a significant number of hospital bed days. Although overall outcomes are better than previously reported (Murray, Thorax 2011), patients with high levels of premorbid dyspnoea have the highest mortality following acute hypercapnic exacerbations of COPD requiring NIV.