Patient adherence refers to the extent to which a patient follows the prescribed treatment plan, including taking medications, attending follow-up appointments, and making lifestyle changes. High levels of adherence can lead to better health outcomes, while low adherence may result in complications or worsening of the condition. Factors influencing patient adherence include understanding the treatment, the complexity of the regimen, and the patient's beliefs about their illness. Healthcare providers, such as doctors and nurses, play a crucial role in supporting adherence by providing clear instructions and addressing any concerns the patient may have.