Decoding grade B pancreatic fistula: a clinical and economical analysis and sub-classification proposal

Abstract

Background: The 2016 ISGPS refined definition of grade B fistula (B-POPF) is predicated on various post-operative management approaches, ranging from prolonged drainage to interventional procedures. However, the spectrum of clinical severity within this entity is yet undefined. Methods: Pancreatectomies performed at two institutions from 2007 to 2016 were reviewed to identify B-POPFs and their treatment strategies. Sub-classification of B-POPFs into three groups was modeled after the Fistula Accordion Severity Grading System (B1: prolonged drainage only; B2: antibiotics/artificial nutrition/somatostatin analogues/transfusions; B3: percutaneous/endoscopic/angiographic procedure). Clinical and economic outcomes, unique from the ISGPS definition qualifiers, were analyzed across subgroups. Results: B-POPF developed in 320/1949 patients (16.4%), and commonly required prolonged drainage (67.8%), antibiotics (70.3%) and artificial nutrition (54.7%). Percutaneous drainage occurred in 79 patients (24.7%) – always in combination with other strategies. Median number of strategies/patient was 2 (range 1–6). Subclasses B1-3 comprised 19.1%, 52.2% and 28.8% of B-POPFs, respectively, and were associated with progressively worse clinical and economic outcomes (Table 1). These results held true when analyzing pancreatoduodenectomies and distal pancreatectomies separately, and were confirmed by multivariable analysis adjusted for clinical and operative factors. Notably, distribution of the B-POPF subclasses was influenced by institution and type of resection (p < 0.001), while clinical/demographic predictors proved elusive. Conclusion: B-POPF is a heterogeneous entity, where three distinct classes with increasing clinical and economic burden can be identified. This classification framework has potential implications for accurate reporting, comparative research and performance evaluation.Table 1Clinical and economic outcome measures stratified by subtype of grade B fistulaOutcome measure n(%)Total Grade B 320 (100)B1 61 (19.1)B2 167 (52.2)B3 92 (28.8)p-valueTotal strategies used to treat the fistula; median (IQR)2 (1–3)12 (2–3)3 (3–4)<0.001Occurrence of non-fistulous complications244 (76.3)29 (47.5)135 (80.8)80 (87.0)<0.001Number of non-fistulous complications; median (IQR)1 (0–2)0 (0-1)1 (0–2)1 (1–3)0.008Total drain duration, days median (IQR)29 (22–39)26 (23-31)26 (19–36)36 (28–58)0.733ICU transfer38 (11.9)6 (9.8)14 (8.4)18 (19.6)0.025Duration of index stay, days median (IQR)18 (10–28)9 (7–13)21 (15–30)20 (9–33)<0.001Readmission84 (26.3)12 (19.7)31 (18.6)41 (44.6)<0.001Multiple readmissions15 (4.7)4 (6.6)1 (0.6)10 (10.9)0.001Fistula-related readmission67 (20.9)028 (16.8)39 (42.4)<0.001Duration of total stay, days median (IQR)21 (14–31)11 (8–14)24 (16–32)25 (19–38)<0.001PMI, mean ± SD0.325 ± 0.1570.221 ± 0.1630.313 ± 0.1390.417 ± 0.130<0.001Fistula ACB mean, ±SD0.274 ± 0.0810.110 ± 00.260 ± 00.370 ± 0<0.001Fistula as the highest graded complication254 (79.4)34 (55.7)141 (84.4)79 (85.9)<0.001Costs∗2.34521.3632.4602.892<0.001median (IQR)(1.637–3.318)(1.040–1.946)(1.801–3.268)(2.177–4.294)Cost variation∗∗+135%+36%+146%+189%–PMI, post-operative morbidity index; ACB, average complication burden.∗Costs data arc inflation-adjusted and expressed as a proportion to the cost of a non-complicated resection.**As compared to the patients experiencing no complications. Open table in a new tab PMI, post-operative morbidity index; ACB, average complication burden. ∗Costs data arc inflation-adjusted and expressed as a proportion to the cost of a non-complicated resection. **As compared to the patients experiencing no complications.