Prevent software (adapted for Lazarus)

Introduction

• Prevent is a GUI application to calculate the incidence and mortality following a risk factor intervention. The software calculates population impact fractions and time impact fractions.
• The methods and software are described in the PhD thesis by Louise Gunning Schepers: https://repub.eur.nl/pub/51053/881123_GUNNING-SCHEPERS-Louisa-Johanna.pdf.
• The Prevent software was developed by Jan Barendragt, who passed away on 3 June 2017. As per his last will and testament, this software has been released under GPL version 3.
• The original software was implemented in Delphi. This version is a conversion to Free Pascal using the Lazarus IDE and libraries.
• There is a manual for the Prevent software as written in Delphi.
• The Lazarus conversion is a work in progress.

Issues with the Lazarus conversion

• [ ] There are two versions for Tgenentity.pzaanpas – one using a cohort perspective and one using an age-group perspective. See disunit.pas.

Notes on the conversion to Lazarus

• Lazarus provides some support for converting applications from Delphi to Lazarus.
• Aside from the automatic conversions, the main structural change was to replace the .mdb Access database inputs with .db SQLite database inputs.
• As a minor technical issue, the datamodule2.inputq1 instance of the TSQLQuery object requires the packetsize property to be -1 – otherwise it defaults to only reads the first ten rows of a query:).
• We provide some R functions that uses mdb-tools and sqlite3 utilities to convert the .mdb database files to .db database files.

Bug fixes

• Multiple memory issues on Ubuntu 24.04 and gtk were resolved by moving to qt5.