Patient adherence: An opportunity for improving outcomes

  • The rapid increase in vertigo disease determinants such as ageing are transforming healthcare needs in developing countries.
  • Medications are effective disease management solutions, but low treatment adherence is widespread.
  • Non-adherence rates reflect a significant opportunity to improve vertigo treatment outcomes in developing countries.
  • Physicians can use a number of simple and efficient strategies to increase adherence.

Vertigo symptoms are a growing burden for healthcare systems worldwide. 

Changing demographics and lifestyle trends are driving an unprecedented increase in the prevalence of chronic conditions, which now affect nearly half of all adults and almost 10% of children worldwide. These diseases pose a significant burden on healthcare systems.1 Low- and middle-income countries are disproportionately affected,3 in part because disease determinants such as population ageing are manifesting dramatically among these populations.2 For example, in Brazil, the proportion of the population over age 65 is expected to double in just two decades, a phenomenon which took over a century in France.2 Vertigo and dizziness are extremely widespread vestibular disorder symptoms, affecting as much as 30% of the general population and their prevalence increases with age.4 These chronic symptoms are attracting increasing attention due to the significant costs and reduced quality of life associated with them.

Medication is an important tool for improving outcomes and lowering costs. 

Vertigo is a significant driver of healthcare utilization from primary to specialist care, and it is associated with significant costs. Estimates of direct costs for lifetime vestibular disease treatment total $227 billion for the over 60 years population over in the US alone. Vertigo symptoms, with financial as well as personal consequences, negatively impact daily living activities and quality of life. In a study performed in the UK and Italy, patients indicated an average of seven days of work missed in the previous 6 months due to vertigo symptoms.4 These trends can be expected to worsen over time with the ageing population.5 Pharmacological treatments represent important disease management solutions but require patient adherence to be effective. 

Managing vertigo and other chronic conditions requires consistent patient adherence 

Medication adherence is defined as, “the degree to which the person’s behavior corresponds with the agreed recommendations from a health care provider.” Adherence has three components: fulfillment, persistence, and compliance

  • Fulfillment refers to the patient initially filling the prescription. 
  • Persistence refers to the treatment being taken for the intended duration. 
  • Compliance refers to the extent to which a patient adheres to prescribed timing, dosage, and other indications.6 

Adherence is complex but changeable. Maintaining high adherence levels requires that patients continuously make choices and adjust their behavior to overcome the various challenges to following their treatment. 

Medication adherence is defined as “the degree to which the person’s behavior corresponds with the agreed recommendations from a health care provider.”

The complexity of patients’ behavior regarding their medication makes real adherence levels and the effect of non-adherence difficult to quantify. Quantitative measures for assessing adherence include the Medication Possession Ratio (MPR) and the Proportion of Days Covered (PDC). 

  • Medication Possession Ratio (MPR) is commonly defined as “the proportion (or percentage) of days’ supply obtained during a specified time period or over a period of refill intervals.” 
  • Proportion of Days Covered (PDC) refers to the number of days when the drug was properly taken as a proportion of days in the observation period. 

Poor treatment adherence is widespread, particularly in developing countries

“Adequate” adherence in the case of an individual patient is generally defined as a ratio of at least 80% for either MPR or PDC.7 Studies using these metrics indicate a global adherence rate of approximately 50%,meaning that roughly half of prescribed medications are not taken;8 adherence rates are even lower in developing countries.9

Adherence remains a significant opportunity area for improving outcomes

Despite the significant costs associated with vertigo symptoms and the significant potential for pharmacological interventions, adherence patterns in vertigo remain unexplored in the literature.10 However, while no research is available for vertigo, adherence patterns for pain medication may be informative. Adherence levels for chronic pain are surprisingly low, with non-adherence to analgesic medication as high as 62%.11 This trend may be due to patients’ tendency to be less adherent or even discontinue treatment when symptoms abate, thus, similar behavior can reasonably be expected for vertigo. Rates of non-adherence behavior are expected to be higher in developing countries, and low adherence to pharmacological treatments for other chronic conditions is linked to poor control of disease risk factors, increased risk of mortality, and extremely high per patient costs.7 Fortunately, behavioral science provides a variety of strategies that prescribers can use in real-world practice to increase patients’ adherence levels.  


  1. Rachelle Louise Cutler et al. (2018). “Economic impact of medication non-adherence by disease groups: A systematic review,” BMJ Open Journals, (8):1, Article e016982. http://doi:10.1136/bmjopen-2017-016982 
  2. World Health Organization (2011). Global Health and Aging, p. 4.
  3. Safia Awan et al. (2017). “Pattern of neurological diseases in adult outpatient neurology clinics in tertiary care hospital,” BMC Research Notes, (10):1, p. 545. https://doi:10.1186/s13104-017-2873-5
  4. Eva Kovacs et al. (2019) “Economic burden of vertigo: A systematic review,” Health Economics Review, (9):1, p. 37. https://doi:10.1186/s13561-019-0258-2 
  5. Louisa Murdin et al. (2015) “Epidemiology of balance symptoms and disorders in the community: A systematic review,” Otology & Neurotology, (36):3, pp. 387–392. https://doi:10.1097/MAO.0000000000000691 
  6. Beena Jimmy & Jimmy Jose (2011). “Patient medication adherence: Measures in daily practice,” Oman Medical Journal, (26):3, pp. 155–159. https://doi:10.5001/omj.2011.38
  7. Laura Alexandra Anghel et al. (2019) “An overview of the common methods used to measure treatment adherence,” Medicine and Pharmacy Reports, (92):2, pp. 117–122. https://doi:10.15386/mpr-1201
  8. Marie T. Brown & Jennifer K. Bussell (2011). “Medication adherence: WHO cares?” Mayo Clinic Proceedings, (86):4, p. 304–14. https://doi:10.4065/mcp.2010.0575 
  9. Adnan Kisa, Eduardo Sabate & Roberto Nuno-Solinis (2003). “Adherence to long-term therapies: Evidence for action,” European Journal of Cardiovascular Nursing, (19):1, pp. 28–29. https://doi:10.1016/S1474-5151(03)00091-4
  10. Tino Prell (2019). “Adherence to medication in neurogeriatric patients: An observational cross-sectional study,” BMC Public Health, (19):1, p. 1012. https://doi:10.1186/s12889-019-7353-5 
  11. L. Timmerman et al. (2016). “Prevalence and determinants of medication non‐adherence in chronic pain patients: a systematic review,” ACTA Anesthesiologica Scandanvica, (60):4, pp. 416–431. https://doi.10.1111/aas.12697