Nicholson, Andrew G.

Abstract The natural history of idiopathic pulmonary fibrosis (IPF) has been characterized as a steady, predictable decline in lung function over time. Recent evidence suggests that some patients may experience a more precipitous course, with periods of relative stability followed by acute deteriorations in respiratory status. Many of these acute deteriorations are of unknown etiology and have been termed acute exacerbations of IPF. This perspective is the result of an international effort to summarize the current state of knowledge regarding acute exacerbations of IPF. Acute exacerbations of IPF are defined as acute, clinically significant deteriorations of unidentifiable cause in patients with underlying IPF. Proposed diagnostic criteria include subjective worsening over 30 days or less, new bilateral radiographic opacities, and the absence of infection or another identifiable etiology. The potential pathobiological roles of infection, disordered cell biology, coagulation, and genetics are discussed, and future research directions are proposed.

Abstract Rationale Treatment and prognoses of diffuse parenchymal lung diseases (DPLDs) varies by diagnosis. Obtaining a uniform diagnosis among observers is difficult. Objectives Evaluate diagnostic agreement between academic and community-based physicians for patients with DPLDs, and determine if an interactive approach between clinicians, radiologists, and pathologists improved diagnostic agreement in community and academic centers. Methods Retrospective review of 39 patients with DPLD. A total of 19 participants reviewed cases at 2 community locations and 1 academic location. Information from the history, physical examination, pulmonary function testing, high-resolution computed tomography, and surgical lung biopsy was collected. Data were presented in the same sequential fashion to three groups of physicians on separate days. Measurements and Main Results Each observer's diagnosis was coded into one of eight categories. A κ statistic allowing for multiple raters was used to assess agreement in diagnosis. Interactions between clinicians, radiologists, and pathologists improved interobserver agreement at both community and academic sites; however, final agreement was better within academic centers (κ = 0.55–0.71) than within community centers (κ = 0.32–0.44). Clinically significant disagreement was present between academic and community-based physicians (κ = 0.11–0.56). Community physicians were more likely to assign a final diagnosis of idiopathic pulmonary fibrosis compared with academic physicians. Conclusions Significant disagreement exists in the diagnosis of DPLD between physicians based in communities compared with those in academic centers. Wherever possible, patients should be referred to centers with expertise in diffuse parenchymal lung disorders to help clarify the diagnosis and provide suggestions regarding treatment options.

Abstract Background To investigate whether the better prognosis of interstitial pneumonias associated with collagen vascular disease (CVD) compared with idiopathic interstitial pneumonia (IIP) is due to higher frequency of the nonspecific interstitial pneumonia (NSIP) pattern in CVD, we compared the outcomes of patients from these two groups with the same histopathologic pattern. Subjects The clinical features and survival of 362 patients (269 with IIP and 93 with CVD) diagnosed using surgical lung biopsy were analyzed. Results The mean survival of the CVD group (131.0 mo) was longer than that of the IIP group (80.5 mo) (p < 0.0001). The patients with usual interstitial pneumonia pattern among the CVD group (n = 36) was younger, female, and predominantly nonsmoking compared with the IIP group (n = 203). Although baseline lung functions were not significantly different, the CVD group survived longer (mean, 177.0 mo) than the IIP group (mean, 66.9 ± 6.5 mo; p = 0.001). By multivariate analysis, younger age, better pulmonary function, and the presence of a CVD were independent prognostic factors. In NSIP pattern, no significant differences in survival, clinical features, or lung function were found between the two groups. Conclusion Our data suggest that the better prognosis of patients in the CVD group is not solely due to the predominance of the NSIP pattern. The prognosis of patients with the usual interstitial pneumonia pattern in CVD is better than in those with idiopathic pulmonary fibrosis, despite the same pathologic pattern. In contrast, in those with an NSIP pattern, the prognosis is similar in both groups.

Abstract Survival is linked to the histopathologic distinction between usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP), the most commonly encountered fibrotic idiopathic interstitial pneumonia. We retrospectively compared the prognostic significance of histopathologic diagnoses, baseline pulmonary function indices, and serial trends in pulmonary function indices (diffusing capacity, FVC, FEV1, the recently defined composite physiologic index) at 6 and 12 months in 104 patients (UIP, n = 63; fibrotic NSIP, n = 41). Survival was lower in UIP than in fibrotic NSIP (p = 0.001) but not in patients with severe functional impairment; mortality during the first 2 years was linked solely to the severity of functional impairment at presentation. The composite physiologic index was the strongest determinant of outcome (p < 0.001). At 6 months, serial diffusing capacity levels (p = 0.003) and histopathologic diagnosis (p = 0.002) were prognostically equivalent. At 12 months, serial pulmonary function trends were the only major prognostic determinant (p < 0.0005 for all variables), with no independent significance associated with the distinction between UIP and fibrotic NSIP. We conclude that at 12 months, serial pulmonary function trends have considerable prognostic value in UIP and NSIP. Their histologic distinction provides no additional prognostic information when pulmonary function trends are clear cut or when functional impairment is severe.

Abstract In idiopathic pulmonary fibrosis, the quantitation of disease severity using pulmonary function tests is often confounded by emphysema. We have identified the composite physiologic index (CPI) most closely reflecting the morphologic extent of pulmonary fibrosis. Consecutive patients with a clinical/computed tomography (CT) diagnosis of idiopathic pulmonary fibrosis (n = 212) were divided into group I (n = 106) and group II (n = 106). The CPI was derived in group I (by fitting pulmonary function tests against disease extent on CT) and was tested in Group II. The formula for the CPI was as follows: extent of disease on CT = 91.0 − (0.65 × percent predicted diffusing capacity for carbon monoxide [DLCO]) − (0.53 × percent predicted FVC) + (0.34 × percent predicted FEV1). In group II, the CPI correlated more strongly with disease extent on CT (r2 = 0.51) than the individual pulmonary function test (DLCO the highest value, r2 = 0.38). A subanalysis demonstrated that the better fit of the CPI was ascribable to a correction of the confounding effects of emphysema. Mortality was predicted more accurately by the CPI than by a pulmonary function test in all clinical subgroups, including a separate cohort of 36 patients with histologically proven usual interstitial pneumonia (CPI, p < 0.0005; FVC, p = 0.002; PO2, p = 0.002). In conclusion, a new CPI, derived against CT and validated using split sample testing, is a more accurate prognostic determinant in usual interstitial pneumonia than an individual pulmonary function test.

Abstract We have retrospectively studied 53 patients with idiopathic pulmonary fibrosis and a histologic diagnosis of usual interstitial pneumonia and evaluated the prognostic significance of four individual histologic features (fibroblastic foci [FF], interstitial mononuclear cell infiltrate, established fibrosis, and intra-alveolar macrophages) using a semiquantitative scale of 0–6. An objective count of FF was also undertaken. Using weighted kappa coefficients, interobserver agreement between pathologists was moderate to good (0.56–0.76). Subjective and objective FF scores were strongly associated (RS = 0.88, < 0.00005). Mortality was independently linked to a high FF score, p = 0.006, and a low percent predicted carbon monoxide diffusing capacity (DlCO), p = 0.01. For pulmonary function, on univariate analysis, the strongest correlations were observed between increasing interstitial mononuclear cell infiltrate or FF scores and greater declines in forced vital capacity (FVC) or DlCO at 6 months. Multivariate models revealed that increasing FF scores were independently associated with greater declines in FVC and DlCO at both 6 and 12 months. Increasing interstitial mononuclear cell infiltrate scores were also independently linked to functional decline, but only at 6 months. These data suggest a reproducible method on biopsy for predicting rate of disease progression in patients with idiopathic pulmonary fibrosis.

Abstract Fibrosing alveolitis associated with systemic sclerosis (FASSc) has a better prognosis than idiopathic pulmonary fibrosis. In view of recent reports that idiopathic nonspecific interstitial pneumonia (NSIP) has a better prognosis than idiopathic usual interstitial pneumonia (UIP), we classified histologic appearances of surgical lung biopsies performed in 80 patients with FASSc. NSIP (n = 62, 77.5%), subcategorized as cellular NSIP (n = 15) and fibrotic NSIP (n = 47) was much more prevalent than UIP (n = 6), end-stage lung disease (ESL, n = 6), or other patterns (n = 6). There were 25 deaths (NSIP 16/62, 26%; UIP/ESL 6/12, 50%). Five-year survival differed little between NSIP (91%) and UIP/ESL (82%); mortality was associated with lower initial carbon monoxide diffusing capacity (DlCO) and FVC levels (p = 0.004 and p = 0.007, respectively). Survival and serial FVC and DlCO trends did not differ between cellular and fibrotic NSIP. Increased mortality in NSIP was associated with lower initial DlCO levels (p = 0.04), higher BAL eosinophil levels (p = 0.03), and deterioration in DlCO levels during the next 3 years (p < 0.005). We conclude that NSIP is the histopathologic pattern in most patients with FASSc. However, outcome is linked more strongly to disease severity at presentation and serial DlCO trends than to histopathologic findings.