INTRODUCTION

AutoISF is designed for advanced users with a profound understanding of AAPS, who have fine-tuned the system to achieve a Time in Range (TIR) of approximately 90% or higher. For those ambitious users seeking further improvement, the methods outlined in this document can prove highly beneficial.

This documentation delineates the automatic adaptation of Insulin Sensitivity Factor (ISF) and provides concise explanations of the weighting factors required to tailor it to individual needs. Comprehensive guides addressing specific scenarios and examples, including outcomes in full loop mode without user-inputted carb or insulin data, will be provided in subsequent documents. Additionally, alternative methods for scaling, activating, or deactivating SMBs are discussed, along with strategies for managing mild to intensive physical activity.

The adaptation of ISF is grounded in understanding unique glucose behavior, resulting in an adaptation factor similar to the Autosense factor. Notably, only ISF is adjusted, leaving other settings unchanged. AutoISF demonstrates rapid responsiveness, analyzing scenarios over the past 10-30 minutes. This agility allows AutoISF to react promptly to issues or recoveries, in contrast to Autosense, which may induce hypoglycemia due to delayed reactions even after returning to the target. Although both can coexist mathematically, disabling Autosense has been a practical choice to avoid such situations.

AutoISF monitors and responds to four distinct aspects of glucose behavior:

1. acce_ISF: This factor is derived from the acceleration of glucose levels.
2. bg_ISF:This factor is derived from the deviation of glucose levels from the target.
3. delta_ISF and pp_ISF:These factors are derived from the delta in glucose rise.
4. dura_ISF: This factor is derived from the duration during which glucose remains elevated.

This system analyzes and adapts to these key elements, ensuring a comprehensive approach to glucose management.

The various factors are compared with each other and against Autosense, with the typically strongest factor being prioritized, although exceptions may apply, as outlined below. These factors operate similarly to the Autosense factor, wherein the profile sensitivity ISF is divided by the respective factor to yield the final sensitivity ISF.

In the SMB-tab, specifically in the Script Debug section, you can easily track the assigned values for the four factors mentioned above during the last loop execution. This section also provides explanations in cases where a factor had to be modified or why it couldn't be utilized. Additionally, interim values such as dura_ISF_average are included in this section. All this information is accessible in the SMB-tab, under the sections Glucose Status, Profile, and Script Debug.

Similar to the Autosense functionality, there are defined upper (autoISF_max) and lower (autoISF_min) limits dictating the extent to which ISF can be adjusted overall. Corresponding to the enabling of SMB, there exists a setting called enable_autoISF, determining whether any of the four ISF adaptations of autoISF are activated or if none are applied.

The settings specific to autoISF are consolidated in its dedicated menu, conveniently located at the end of the OpenAPS SMB menu. A screenshot illustrating these settings is attached for reference. An alternative method for locating them is to utilize the filter feature at the top of the Preferences page, which facilitates the search for all settings containing the specified string entered in the filter field.