We found that malignancy as indication for PEG was significantly associated with higher mortality at 90 days after the procedure, compared to neurological disease as indication. There was also a clear, although not statistically significant, trend for higher mortality at 30 days among those that had malignancy as indication. We also found several other factors that were associated with higher mortality rates and more complications, including older age, female sex, diabetes, heart failure, increasing CRP levels and lower BMI.
The main exposure and outcome of our study contrasts with those of several previous studies, which found higher mortality rates for those suffering from neurological deficit, whereas in our study malignancy was associated with a higher mortality rate. Compared to previous studies, the proportion of patients with malignancy in our study was much lower than that of patients with neurological disease. This is probably explained by differences in the criteria for referral in different regions of Sweden as well as in other countries, i.e., patients with malignancy are probably referred for PEG procedures more rarely and later in Region Norrbotten, compared to patients in previous studies. There was no significant difference in the complication rates between the two groups, indicating that the higher mortality rate is a consequence of greater comorbidity and frailty among patients with malignancy, rather than a consequence of the procedure itself. Earlier referral for patients with malignancy in need for PEG would probably benefit these patients, especially when considering the high mortality rates among those with malignancy.
Furthermore, low BMI as a risk factor for mortality at 90 days also indicate that many of our patients would benefit from PEG at an earlier stage of their disease, since the indication for PEG in many cases is to achieve sufficient nourishment. Our finding that higher CRP levels are associated with worse outcomes is not surprising, has been shown in previous studies, and should be considered an indication of a more severe underlying condition (15, 17, 22, 23). The finding that underlying diabetes and heart failure increases the risk of mortality has also been confirmed in previous studies (20, 21, 23).
The higher mortality rate among women was not something that we expected to find and has not been reported in previous studies. In all, 55% of the patients in our study were men, which is in line with previous studies, showing that men account for 56–71% of all included patients (13, 14, 18, 20, 23). This indicates that men are referred and accepted for PEG more often. Probably, there are more women who could benefit from PEG but are either never referred for the procedure or are denied more often than men are. This is something that warrants further research.
While the frequency of minor complications was somewhat lower compared with previous studies, there was a surprisingly high number of major complications in our study. An explanation for this is the high rate of aspirational pneumonias. However, aspiration pneumonias might be a complication of the underlying condition which indicated the procedure, as well as a complication of the procedure itself, and hence it could be discussed whether it should be measured as a complication or as a result of the underlying disease. In this study, we included all reported aspirational pneumonias as a major complication, and hence the high number of major complications should be interpreted with care, although clinicians should be aware of the risk of aspiration pneumonias regardless of the cause of it. If we excluded aspiration pneumonias as a complication, the number of major complications would be 15 (4%), which is more in line with previous studies.
There was a large difference in outcomes between the two hospitals in our study, where one hospital performed better both regarding mortality and major complications. Given that the equipment, routines and to some extent the surgeons do not vary between the two hospitals, we believe that the difference is probably explained by differences in patient referral patterns. This is supported by the fact that the hospital with a significantly higher mortality rate performed much fewer PEG procedures than expected given the population in the catchment area. To further examine this, we also compared patient characteristics between the two hospitals, and the patients at the hospital with less adverse outcomes were on average 4 years younger, had less comorbidities and lower CRP. These findings together with the findings of the higher mortality rates for patients with malignancy and among women have been reported back to the hospitals which are now improving local referral routines with the goal of a more equal care between the hospitals.
A major strength of this study is the wide inclusion criteria where we included all adult patients in an entire region in Sweden, which limits inclusion bias. However, being a retrospective study, it has some obvious flaws such as the absence of a standard protocol for patient follow-up. We believe this limits our understanding of complications, especially for minor complications, a theory supported by the fact that we found fewer of these than expected when comparing our results to previous studies. Death, however, is very robustly reported in medical journals, minimizing bias regarding this. Another flaw is our understanding of the preoperative status among the patients, preferably we would have had information on for example ASA (American Society of Anesthesiologists) class, as well as a more standardised measurement of comorbidities using for example the Charlson Comorbidity Index, as presented in a previous study on PEG.(24) This data was however not collected since it would have required searches in other databases which we had no access to. The external validity of our study is questionable due to the possible differences in referral patterns in our study compared with previous studies as well as other regions. However, we believe our study make a good contribution to the understanding of complications and mortality after PEG procedures in a routine clinical setting, especially since our study includes two different hospitals and a relatively large number of patients.