Six‐minute walk distance target in elderly patients with idiopathic pulmonary arterial hypertension – consideration of predicted values

Summary Background The number of elderly patients diagnosed with idiopathic pulmonary arterial hypertension ( IPAH ) is increasing. A 6‐min walk distance (6 MWD ) > 380 m on therapy is associated with improved survival in IPAH . As exercise capacity is naturally decreasing with age, treatment goals for elderly patients might be different from those established for younger patients. Methods Consecutive adult patients diagnosed with IPAH between 1/2005 and 7/2012 were retrospectively included. We analysed the prognostic value of 6 MWD targets (in metres and % predicted) with respect to age at diagnosis. Results The mean (±  SD ) 6 MWD in 23 patients aged > 65 years at diagnosis compared with 22 younger patients was significantly lower at baseline (262 ± 69 vs. 356 ± 128 m; p = 0.011) and first follow up (310 ± 75 vs. 377 ± 137 m; p = 0.045), while the corresponding % predicted values were similar (62 ± 16% vs. 63 ± 21%; p = 0.854, and 74 ± 16% vs. 68 ± 21%; p = 0.267). The established treatment target of > 380 m 6 MWD was met by only 13% of elderly compared with 46% of younger patients (p = 0.016), while the corresponding 6 MWD of 78% predicted was exceeded by similar proportions (48% and 46%, respectively; p = 0.873). Survival of patients walking > 380 m or 78% predicted on first follow up was significantly better compared with patients not exceeding the respective threshold (100% vs. 72% and 95% vs. 67% at the end of follow up, respectively; p < 0.05 each). Conclusion Expression of the 6 MWD target as % predicted equalises age‐related differences and has similar prognostic power compared with absolute values in patients with IPAH . As elderly patients are less likely to reach the absolute 6 MWD threshold, the use of % predicted could be helpful in their individual assessment and adaption of targeted therapy.