Background/Purpose: Granulomatosis with polyangiitis
(GPA) is associated with severe end-organ damage (e.g., renal failure) and treatment-related
complications (e.g., severe infection) which often lead to
hospitalization with major resource use.  However, no data on hospitalization
trends and associated mortality are available.  We evaluated recent trends in nationwide
hospitalization and in-hospital mortality among patients with GPA. 

Methods: We
used the National Inpatient Survey (NIS) which is the
largest all-payer inpatient database in the US and includes data and sampling
weights from over 1,200 hospitals across 44 states. We studied all hospitalizations
of adults (³18 years) with a primary discharge diagnosis of GPA (ICD 9: 446.4)
between 2001 and 2011.  We
investigated trends in hospitalization and mortality by comparing GPA to
overall inpatient hospitalization trends. 
All analyses were performed using hospital-level sampling weights
provided by the NIS to obtain US national estimates.

Results: From
2001 to 2011, the rate of hospitalization for GPA remained stable from
0.76/100,000 persons to 0.78/100,000 persons.  The mean age tended to get younger from
56.9 yrs to 55.1 yrs and there was a slight male
predominance (40.6% +/- 3.1 vs. 50.0% +/- 2.9; P-for-trend=0.0001) over the
study period. From 2001 to 2011, the mean length of stay remained stable,
between 9.7 +/- 0.6 and 8.6 +/- 0.5 days (P-for-trend 0.24), but there was a
significant decline in in-hospital death from 7.7% (+/-2.7%) in 2001 to 2.6%
(+/-1.5%) in 2011 (Figure 1)
(P-for-trend < 0.0001). Overall, the annual relative change in GPA mortality
was -9.96% (95% CI: -14.3 to -5.6) and the annual absolute change was -0.46%
(95% CI: -0.66% to -0.25%). This was a significantly greater decline than
overall inpatient hospitalization mortality (annual relative change of -2.5%
95% CI -2.7% to -2.2% and annual absolute change of -0.06%, 95% CI: -0.06% to
-0.05%). Among those who died during a hospitalization when GPA was the primary
diagnosis in 2011, the most common secondary diagnoses were respiratory
failure, chronic kidney disease, and lower respiratory disease. 

Conclusion:
Between 2001 and 2011, hospitalization and length of stay for GPA remained
stable but in-hospital mortality declined in this dataset representative of all
US hospitalizations. This decline was significantly greater than that of the
background US in-hospital mortality rate. The declining in-hospital mortality
rate may be due to earlier recognition of GPA, shifts in treatment that
emphasize less cyclophosphamide use and more tempered use of glucocorticoids,
and secular trends in the management of infections and end-organ
complications.

FIGURE
1: Nationwide Trends in In-Hospital Mortality of GPA Patients