In this study majority of participants underwent major abdominal surgery, had lower preoperative and postoperative serum albumin level than the standard lower limit. The mean postoperative albumin was even lower than mean preoperative value. This observation explains the theory of decrease in albumin level due to inflammation and surgical trauma (6); similarly a reduction in albumin levels after surgical trauma is related to generalized inflammation, called systemic inflammatory response syndrome, which is characterized by increased capillary leakage of albumin. Also, in the study of early decrease in postoperative albumin as predictor of complications, there was significant decrease in postoperative albumin levels however the final analysis did not suggest its predictive role.
In contrast to this study were preoperative serum albumin level was not an independent factor for adverse outcome; in other study preoperative low albumin was an independent and significant risk factor for adverse surgical outcome (6). This may be associated with the involvement of only colorectal cancer patients in the study. These patients were at higher risk of malnutrition due to cancer-induced metabolism, lower dietary intake and effect of tumor necrosis factor-alpha on alteration of liver protein production.
Percentage decrease of serum albumin (delta albumin) after surgery was higher in participant with even lower postoperative albumin levels. In this study delta albumin was associated with adverse postoperative surgical site infection, delayed wound healing and death within 30 days. These findings correlate with a study done in Australia to evaluate the value of delta albumin to surgical complications in patients who underwent bowel resection due to Crohn’s disease. Higher delta albumin levels were significantly associated with postoperative complications namely intra-abdominal abscess, anastomotic leak, reoperation and death. Neither preoperative nor postoperative serum albumin was an independent risk factor for surgical complications (7). Despite difference in ethnicity between the Australian participants and our participants; there were similar methods in calculating the percentage difference of albumin levels and correlating them with postoperative outcomes.
The delta albumin (ΔAlb) was an independent risk factor for severe complications in CRC patients after curative laparoscopic surgery(8). The study done in Thailand also revealed similar findings that hypoalbuminemia is a potential predictor of delayed recovery of bowel function postoperatively and significantly associated with postoperative complications(9). In both cohorts, there were similar risk of hypoalbuminemia due to malignancy hence depicted the similar outcome pattern.
In this cohort postoperative adverse outcome were evident to approximately 46%, these include surgical site infection, delayed wound healing and death with 30 days post operatively. However other factors were associated to surgical outcome; longer operation time of more than two hours was 73% suggestive of poor outcome than the shorter surgeries. This may be due to longer surgical trauma, longer inflammatory phase post-surgery and higher risk of delay recovery time.
Also patients who underwent elective operations had protective effect of 40% compared to emergency cases. Elective patients were clinically more stable with fair nutritional status. This observation may be attributed to less morbid condition of elective patients. In rectal surgery hypoalbuminemia combined with higher ASA classification was significant associated with wound infection, remote infections such as pneumonia, and anastomotic leakage, other complication included reoperation and death(10). This may be attributed other comorbid situation like hypertensive heart disease and diabetic mellitus together with operative stress.
In the view of how accurate the decrease in albumin level would predict the adverse outcome; delta albumin showed association with surgical site infection. An area under receiver operating characteristic curve (AUC) of 0.72 (95% CI 0.55 0.89) was obtained which is a good predictive power. The best cutoff value was 11.61% with the sensitivity of 76.92% and specificity of 51.72%.This explains how good perioperative decrease in serum albumin is a predictor for potential surgical complications with 30 days of surgery. The findings were consistent with other studies which delta albumin of more than 15% was a cutoff point with higher sensitivity and specificity (8). Also in studies done in China, Thailand and Australia, the cutoff point of 15.0%, 13.2%, and 24.27% were associated with larger AUC and high sensitivity and specificity. These similar findings render the predictive accuracy of decrease of serum albumin as a predictor of adverse surgical outcome (1, 7, 8).
We conducted a prospective study where individual follow-up of each study participants both preoperatively and postoperatively was done, this maximized reliability of collected information as there was less recording and recall biases. However the study was conducted in a single institution; this may affect a true sample representation of developing world. The recruitment time for participants was as short as six months; the number of participants was small, this may affect the power of this study. This study did not take the impacts of liver function and body fluid volume on serum albumin concentrations into consideration. An adequate function of the hepatocytes is a prerequisite of production of normal serum albumin levels, therefore preoperative assessment of liver functions tests would exclude confounding liver diseases as well as explaining a low preoperative albumin. Therefore abnormal liver function tests would provide important exclusion criteria for the studied patients.