This study evaluated the effects of HTN and DM, alone or in combination, on the postoperative outcomes of elective noncardiac surgery in cancer patients. Our findings suggest that patients with preoperative comorbidities, such as HTN and DM, alone or in combination, do not have an increased risk of adverse postoperative outcomes. Rather preoperative risk (ASA status) and operative time affected the risk of postoperative adverse events.
Preoperative clinical evaluation of patients undergoing elective surgery can be performed for multiple purposes, including for detecting possible disorders that may compromise a satisfactory postoperative course . Through medical history and physical examination, pre-existing or unknown diseases that may increase the risk of complications during the perioperative period can be detected. HTN and DM have a high prevalence among the population. In patients with neoplasms, the prevalence of HTN is around 40%, reaching 74% in the group aged over 65 years [6, 12–15]. Similarly, in this population, DM has a prevalence of 21% .
It has been considered that the presence of HTN or DM alone, or both pathologies together, may increase the likelihood of postoperative complications after non-cardiac surgery, as these are risk factors for cardiovascular disease [17–19]; however, the absence of previous evidence of the association of HTN and/or DM with the occurrence of postoperative complications prompted us to perform this investigation to clarify whether these conditions can in fact impact the postoperative course in cancer patients undergoing intermediate/high risk surgery. Regardless of the presence of comorbidities, intermediate- and high-risk surgeries have a higher intrinsic chance of involving adverse perioperative events, particularly those related to the mobilisation of body fluids and the duration of the procedure. Intermediate-risk surgeries are procedures associated with adverse outcomes in 1‒5% of cases, and high-risk surgeries are associated with complications in > 5% of cases .
Our results indicated that patients with HTN and DM, alone or in combination, that is well-controlled presurgically, does not impact the postoperative outcomes of cancer patients undergoing non-cardiac intermediate/high-risk surgical interventions, as compared to patients without DM or HTN. A recent study  that evaluated 203 patients in a mixed population (with and without cancer), but with risk factors for cardiovascular complications, who underwent major non-cardiac thoracic surgery also found no association between the presence of HTN or DM with adverse outcomes in the postoperative period.
Abnormalities on chest radiography and ECG were not associated with an increase in morbidity and mortality in our study, corroborating findings by previous studies that showed that requesting these preoperative tests for asymptomatic patients offers little or no benefit [21–23]. In elderly individuals, chest X-ray may be abnormal, but without necessarily increasing the surgical risk . There are also doubts in the literature regarding the benefit of using ECG in the preoperative period in asymptomatic patients, considering that the incidence of abnormal results increases with age and may not be related to increased adverse outcomes [22, 23].
In the composition of surgical risk, the presence of comorbidities is relevant. In our study, preoperative risk assessment was categorised into ASA I/II and ASA III/IV risk status. We noted that the presence of a higher surgical risk was an independent predictor of postoperative complications, which has been established previously. This indicates that we had suitably adjusted for confounding factors. In addition, we performed multivariate logistic regression analysis with and without including this surgical risk variable; the presence of these comorbidities did not correlate with an increase in the number of adverse events, irrespective of inclusion of ASA status.
Most procedures (70%) had an operative time < 3 hours; patients with a prolonged surgical time (> 5 hours) had significantly more adverse outcomes, as corroborated by previous studies [24, 25]. Early recognition and intervention for any perioperative complications may help these patients and also reduce health care costs.
Our study had some limitations that were mainly inherent to the retrospective analysis of administrative databases. The study was conducted retrospectively at a single centre, which might limit the generalisation of its results. Additional limitations include that the vast majority of procedures had an effective duration of surgery of no more than 3 hours, and knowing that the surgical time is a predictor of postoperative complications, it is not clear whether these comorbidities would become significant in longer surgeries. In addition, most patients in this study were female. Given the scarcity of studies seeking to correlate the characteristics inherent to patients in the preoperative period with the outcomes in the postoperative period, further research is needed improve understanding of the impact of these comorbidities in different populations of individuals submitted to more diverse surgical procedures.
In summary, with the use of a representative database, we found that, in a population of cancer patients undergoing elective moderate/high risk surgeries, a previous diagnosis of HTN and DM, alone or combined (properly controlled), did not correlate with an increase in in-hospital morbidity and mortality.