Abstract
Background: Pressure ulcers can be very painful and usually take a long time to heal. The right multimodality treatments are needed to minimize this burden. However, pressure ulcers closure oftentimes fail. It is required to establish the right moment for wound closure. The degradation rate of the extracellular matrix as a result of matrix metalloproteinase (MMP) and tissue inhibitors of matrix metalloproteinase (TIMP) activity can be a good predictor of the success of surgical closure. Objectives: We propose a solution by setting the TIMP-1 / MMP-9 cut-off point ratio to determine wound closure success in pressure ulcers. Methods: This was a hospital-based nested case-control study at Hasan Sadikin General Hospital, Bandung. Data were collected from April 2012 to February 2014. Wound assessment was done every week until the third week to consider the successful and unsuccessful wound closure group. The relationship between variables was analyzed with bivariate analysis, while its strength was assessed by the contingency coefficient. The TIMP-1 / MMP-9 ratio cut-off point was determined using the Receiver Operating Characteristic (ROC) curve. Results: Twenty-four patients who underwent wound closure were enrolled as respondents. The relationship of TIMP-1 with the success rate of pressure ulcer closure did not show significant differences (P-value = 0.545). The MMP-9 in the group that succeeded and failed also did not show a significant difference (P-value = 0.367). However, the combination of TIMP-1 / MMP-9 ratio with cut-off point 0.732 was significantly different between the successful and unsuccessful group (P-value = 0.032; C = 0.610). Conclusion: TIMP-1 / MMP-9 ratio > 0.732 is related to the success in wound closure of pressure ulcers. Thus, it is important that surgeons measure the ratio on preoperative pressure ulcer patients due to their proven benefits in predicting the success rate of surgical closure.

Key words: pressure ulcer, TIMP, MMP, wound healing