C l i n i c a l S t u d i e s 614 Febrile neutropaenia in apparently stable outpatients A Carmona-Bayonas et al SPSS 15.0 software (SPSS Inc., Chicago, IL, USA). All test were two- sided, and P-values o0.05 were considered significant. RESULTS The medical records of 861 valid episodes of FN were reviewed. We found that in 692 episodes (80%), there were neither clinical findings of instability nor a serious infection at the onset. Hence, according to the medical record, we classified them as ASPs (Figure 1). The other 169 episodes (20%) were classified as CUPs. The most frequent causes for classification as CUP were severe infections, but there were also complications unrelated to neutropaenia, such as embolism or arrhythmia. We analysed what happened with ASPs during the hospital admission. Only 51 patients (7.3%) in the ASP group developed a serious complica- tion, a rate in the range of low-risk MASCC group. The most frequent complications were acute respiratory failure (27 events), hypotension (25 events) and acute renal failure (11 events). Nine patients (1.3%) died after admission and the cause of death was clearly related to infection in seven of them (1%). Other complications were observed at a lower frequency (Table 3). We observed a 6.2% rate of bacteraemia (43 episodes), which was lower than previously reported (Klastersky et al, 2007), a fact that we attributed to the selection of stable patients. We also found 22 cases (3.2%) of delayed lung infiltrates. These categories showed some overlap: 14 patients with bacteraemia and 7 patients with delayed lung infiltrates had serious complications. The main features of the patients and the febrile episodes are shown in Table 4. To determine which prognostic factors were relevant in ASPs, a case – control study was designed. We performed a univariate analysis as shown on Table 5. The significant factors associated with complications were grouped in three categories: (1) baseline characteristics and comorbi- dity: age X65 years, male, ECOG X2, lung tumours, absence of breast cancer, COPD and chronic heart failure; (2) biological variables: albumin o3 mg dl 1, proteins o6.4 mg dl 1, uraemia 430 mg dl 1, stress hyperglycaemia, monocytes o200 mm 3 and platelets o1 00 000 mm 3; and (3) clinical characteristics of the febrile episode: stomatitis NCI grade X2, productive cough, MASCC score o21 and constitutional syndrome. Interestingly, lung cancer showed an increased risk of complications (OR 3.43), mainly acute respiratory failure, whereas breast cancer was a protective factor (OR 0.34). In the multivariate analysis, six variables constituted independent risk factors: ECOGX2, COPD, chronic heart failure, stomatitis grade X2, monocytopenia and stress hyperglycaemia (Table 6). The absence of a validation set precluded a head-to-head comparison between our model and MASCC, but we analysed the distribution of the MASCC scores in the cases and controls (Table 5). We observed that 85% of the sample had a MASCC index X21. We calculated the following parameters to detect complica- tions: sensitivity 36%, specificity 94%, positive predictive value 32%, negative predictive value 94.9%, positive likelihood ratio 6, Table 3 Distribution of acute serious complications n (%)a 27 (28) 25 (26) 11 (11) 9 (9.5) 6 (6.3) 4 (4.2) 4 (4.2) 3 (3.1) 2 (2.1) 2 (2.1) 1 (1) 94 Complication Acute respiratory failure Hypotension Acute renal failure Death Altered mental status Acute heart failure Serious bleeding Acute abdomen Arrhythmia Disseminated intravascular coagulation Unstable angina Total 861 Patients with cancer and febrile neutropaenia aNumber of complications. Multiples complications for one patient are shown here. Evaluation in the outpatient clinic area Transfer to an in-patient ward for urgent stabilisation ASP group: 692 patients (80%) CUP group: 169 patients (20%) All of them were admitted Cases: 51 patients (7.3%) had a serious complication Figure 1 Flowchart summarising the study design. British Journal of Cancer (2011) 105(5), 612 – 617 641 Discharged without serious events Random selection of controls ratio 1 : 2 Controls: 124 patients & 2011 Cancer Research UK