Background:
Interstitial lung diseases (ILDs) are associated with a high burden of disease, but
it remains unclear if there are entity-specific differences in quality of life (QoL).
Our aim was to assess QoL and to compare assessment by the generic EQ-5D-5L with the
disease specific King's Brief Interstitial Lung Disease questionnaire (K-BILD) across
different ILD entities.
Methods:
Our data refer to 229 patients of the ongoing HILDA observational study. Based on
prevalence in the study sample, interstitial idiopathic pneumonias (IIPs), sarcoidosis
(SAR) and other ILDs were defined as entities of interest. In an univariate analysis
we compared entity-specific mean scores (+ Standard deviation) of K-BILD and EQ-5D
(VAS and experience based values (ebvs)) via ANOVA. Within a multivariate analysis,
Generalized Linear Models were performed to assess entity-specific QoL-differences
adjusted for age, sex, education, recruitment center, smoking status, FVC and DLCO
% predicted, and frequency of comorbidities.
Results:
Univariate QoL comparisons between IIPs (n = 80 (34.9%)), SAR (51 (22.3%)) and Others
(98 (42.8%)) revealed no significant differences in QoL(EQ-5D ebvs 0.68 (0.167) 0.66
(0.18) 0.64 (0.17) p = 0.2951; VAS 63.2 (19.56) 62.63 (18.14) 59.27 (19.28) p = 0.347;
K-BILD 54.11 (10.81) 54.58 (12.79) 52.57 (11.74) p = 0.5315).
In the multivariate model IIP patients showed significantly better? QoL than those
with SAR for EQ-5D ebvs (0.74 vs. 0.65 p = 0.0186) VAS (68.7 vs. 59.5 p = 0.0289;
and K-BILD (59.2 vs. 54.2 p = 0.0473). Compared to other ILDs QoL in IIP was better
regarding EQ-5D ebvs (0.74 vs. 0.66; p = 0.0014) and VAS (68.7 vs. 59.7 p = 0.002)
but not if assessed by K-BILD (59.2 vs. 55.8 p = 0.0575). Irrespective of entity,
higher comorbidity burden had a negative impact on QoL and a higher FVC % predicted
value a positive impact.
Discussion:
Our analysis revealed better generic QoL in IIPs compared to other ILDs which by trend
also holds for disease- specific QoL. Further investigations are needed to determine
the reasons for this phenomenon. Particularly a grouping of ILDs with similar clinical
characteristics might help to understand the associations between QoL and particulars
of ILD more comprehensively.
