A public health officer in a district of Maharashtra is conducting a survey to understand the burden of diabetes in the population. She identifies 500 individuals with diabetes from a total population of 50,000 on a single day in January 2024. Three months later, in April 2024, she conducts another survey and finds 520 individuals with diabetes in the same population. What is the most appropriate next step to determine whether the increase in diabetes cases represents a true increase in disease occurrence in the community?