Introduction
According to the Centers for Diseases Control and Prevention, >34 million people in the USA have diabetes mellitus (DM) withtype 2 DM (T2DM) accounting for 90%–95% of all DM cases.1 DM is disproportionally prevalent among racial/ethnic minorities and people with lower education levels.1 DM is also economically taxing; the USA spends approximately US$327 billion annually on DM-related costs.2
Persons with T2DM must actively participate in their life-long care to successfully manage their disease.3 Without adequate engagement in care, people with T2DM are likely to have higher glucose levels, which may result in severe complications (eg, heart disease, kidney disease).4 Specifically, persons with T2DM need to perform various self-care activities, including lifestyle management5 and attending regular medical appointments,6 to achieve optimal glycemic control. In particular, persons with T2DM should attend medical appointments every 3–6 months to evaluate hemoglobin A1c (HbA1c)6 and annually to assess microvascular complications.7 Regular medical appointments that are patient-centered also represent critical opportunities for persons with T2DM to receive individualized education and treatment plans; for the healthcare team to support persons with T2DM in self-care and to review, assess and adjust treatment plans in a timely manner.6
Despite its significance, recent statistics show that 12%–36% of persons with T2DM do not keep their regular medical appointments.8 9 Missed regular medical appointments in T2DM care pose a significant threat to patients’ glycemic outcomes. For example, persons with T2DM who missed regular appointments had a 24%–64% greater odds of having poor glycemic outcomes than those who did not,10 11 and 60% greater odds of rehospitalization.12 Likewise, missed medical appointments pose a financial burden at the healthcare system level.13–15 A DM clinic estimated that the average cost of no-show per patient was US$110 in 2004.16 Missed DM-related appointments also increase societal costs where the waitlist is longer for other patients to get needed care.13 14 17
To improve the quality of T2DM care and to better support those with T2DM in achieving glycemic control, it is essential to understand the factors that are associated with missed regular medical appointments. Few prior systematic reviews addressed some aspects of missed appointments among persons with DM. For example, one meta-analysis conducted in 2007 (n=47 studies involving children, adolescents or adults with either type of diabetes) examined the effect of depression on various DM self-care activities and found that its effect was the strongest on missed medical appointments compared with overall treatment adherence composite measures, diet, medication, exercise or glucose monitoring.18 Another review of 50 studies conducted in 2008 _targeted uninsured adults with DM revealed that depression or other psychological diagnoses, along with poverty, lack of transportation, personal belief that the appointment did not help, lack of childcare, presence of a sick child and forgetfulness were significantly correlated with missed appointments in the uninsured, low-income samples.19 A systematic review conducted in 2016 including 24 studies of patients with either DM or hypertension in an outpatient setting worldwide identified 83 factors associated with missed appointments. The authors categorized factors into patient (eg, mental state, demographics, alcohol and tobacco use), disease and medication (eg, poor baseline HbA1c, poor lipid profile) and healthcare provider-related factors (eg, scheduling factors, provider characteristics).20 Similarly, another systematic review conducted in 2019 with 34 studies of patients with DM across the lifespan summarized factors associated with missed appointments and interventions to minimize missed appointments. The review organized factors associated with missed outpatient appointments into five categories, including patient characteristics (eg, age, gender, duration of DM), socioeconomic factors (eg, financial pressures, smoking/alcohol intake), ethnicity and culture (eg, ethnic minority), illness perceptions and attitudes (eg, dismissive behavior) and other factors (eg, comorbidities, receiving diabetes education).21
While these reviews offer some helpful insights, they were either too narrowly focused (eg, the effect of depression on medical visits or uninsured patients only), published >10 years ago,18 19 included a wide range of age groups,18 21 or included disease conditions beyond DM.20 Given that the management of DM in youth is different from adult patients22 and that the disease progression and treatment plans differ considerably,23 a systematic review that specifically addresses correlates of missed regular medical appointments among adults with T2DM is warranted. The purpose of this systematic review was to synthesize existing literature to identify factors that are associated with missed appointments by adults with T2DM. In particular, given limited consistency as to how missed appointments (ie, definition and source of data) are operationalized in DM care,21 24 we attempted to extract the definition of missed appointments and source of data used in each study. To present comprehensive and theoretically relevant factors that are salient to adults with T2DM, we organized factors that are associated with missed appointments by adults with T2DM using the Quality-Caring Model. The Quality-Caring Model uses the structure-process-outcome framework to illustrate how the characteristics of the patient and the provider (structure) may impact the interpersonal encounter (process), and how the interpersonal process may influence patient outcomes, such as attending regular medical appointments in DM care.25