Table 1 Study characteristics

Lloyd, 2005, UK [25]

To elicit the preferences of people with epilepsy for changes in adverse effects and the level of seizure control, and to determine willingness to pay for improvements in adverse effects and seizure frequency

[148]

Literature review, drug monographs and discussion with epilepsy advocacy group

1. Seizure control [you become free of seizures, your seizures are reduced by more than half (75%), or your seizures are reduced by half (50%)]

2. Weight change [you gain 26 lbs, you gain 13 lbs, or you lose 13 lbs]

3. Skin rash [you have no skin rash, you have a 1 in 10 chance (10%) of developing skin rash, or you have a 1 in 5 chance (20%) of developing skin rash]

4. Concentration [your concentration is unaffected, you have a 1 in 10 chance (10%) of the drug affecting your concentration, or you have a 1 in 5 chance (20%) of the drug affecting your concentration]

5. Alopecia [you have no hair loss, you have a 1 in 10 chance (10%) of hair loss, or you have a 1 in 5 chance (20%) of hair loss]

6. Feeling sick [you do not feel sick, you have a 1 in 10 (10%) chance of feeling sick or being sick, or you have a 1 in 3 (33%) chance of feeling sick or being sick]

7. Payment vehicle cost [the drug will cost you an extra £25 per month, the drug will cost you an extra £50 per month, or the drug will cost you an extra £75 per month]

Manjunath, 2012, USA [26]

To quantify the relative importance of treatment outcomes of add-on AEDs and the extent to which patients with symptoms of partial seizures were willing to accept short-term and long-term side effects in exchange for better seizure control and estimate patients' WTP for treatment outcomes

[193]

Literature review, consultation with epileptologists and patient interviews

1. Number of seizures [zero seizures, 75% fewer seizures, 50% fewer seizures, and 25% fewer seizures]

2. Duration of short-term effects [none—last for 1 week, and last for 4 weeks]

3. Long-term fatigue or moodiness [none—cause some difficulty doing daily activities]

4. Long-term confusion or memory problems [none—cause some difficulty doing daily activities]

5. Difficulty urinating [none, half the time, and almost always]

6. Weight change in 6 months [15 pound weight loss, no weight loss or gain, and 15 pound weight gain]

7. How often you take the medicine [once a day, twice a day, and 3 times a day]

8. Personal medicine cost [low cost range [$0 per month ($0 every 3 months), $25 per month ($75 every 3 months), $75 per month ($225 every 3 months) $150 per month ($450 every 3 months)] – [high cost range [$0 per month ($0 every 3 months), $75 per month ($225 every 3 months), $150 per month ($450 every 3 months), $300 per month ($900 every 3 months)]]

Ettinger, 2018, USA [22]

To determine the relative importance of AED attributes to treatment preference among both patients and neurologists, and the level of concordance and discordance between the two groups of participants. regarding AED attributes for treating epilepsy

[518 patients and 202 neurologists]

Literature review, consultation with 4 neurologist with experience researching and/or treating epilepsy

1. AED efficacy [completely seizure-free, seizures reduced by more than half, seizures reduced by a half, and seizures reduced by less than half]

2. Dosing frequency [one time per day, two times per day, three times per day, four times per day, and five or more times per day]

3. Coordination/balance side effects [0% chance of problems, 5% chance of problems, 10% chance of problems, 15% chance of problems, and 20% chance of problems]

4. Psychiatric side effects [0% chance of problems, 5% chance of problems, 10% chance of problems, 15% chance of problems, and 20% chance of problems]

5. Diminished energy level [0% chance of problems, 5% chance of problems, 10% chance of problems, 15% chance of problems, and 20% chance of problems]

6. Dietary restrictions [can swallow, crush, mix with food—cannot swallow, crush, mix with food]

Holmes, 2019, UK [23]

To compare patient-defined benefit-risk preferences with the results of a clinical trial of AEDs and to assess differences between patient subgroups

[280: 177 patients with a recent or established diagnosis, 103 women of childbearing potential]

Qualitative study of epilepsy patients to select important outcomes derived from clinical trials and validated outcome measures and nominated by the patients. The validity of top 10 outcomes were examined using cognitive interviews with patients and a meeting with prescribing physicians. The top 5 attributes were used

1. Seizures stop [5 in 10 people -0.5- or 3 in 10 people -0.3-]

2. Fewer seizures [3 in 10 people -0.3- or 1 in 10 people -0.1-]

3. Memory problems [1 in 100 people -0.01- or 7 in 100 people -0.07-]

4. Depression [1 in 100 people -0.01- or 8 in 100 people -0.08-]

5. Feelings of aggression [1 in 100 people -0.01- or 8 in 100 people -0.08-]

6. Harm to your fetus if the patient gets pregnant while taking this medication [2 in 100 pregnant women -0.02- or 9 in 100 pregnant women -0.09-]

Hua, 2020, China [24]

To explore Chinese patients’ risk–benefit preferences and willingness-to-pay for AEDs treatment [151]

Literature review, calibrated by neurologists and patient survey

1. Efficacy of AED [seizure-free -100% controlled-, seizure frequency is reduced by more than half -75% less-, or seizure frequency is reduced by half -50% less-]

2. Digestive adverse reaction [0 in 10 people -0%-, 1 in 10 people -10%-, or 3 in 10 people -30%-]

3. Duration of side effects in neuropsychic systems [none, last for 1 week, or last for 4 weeks)

4. Dosing frequency [once a day, twice a day, or thrice a day]

5. Effects of AEDs on the fetus [3 in 100 people -3%-, 6 in 100 people -6%-, or 10 in 100 people -10%-],

6. Drug costs [200¥ per month, 400¥ per month, or 600¥ per month]

Sinha, 2022, USA [28]

To determine patient acceptability of benefit-risk trade-offs in selecting treatment options for drug-resistant mesial temporal lobe epilepsy, including open brain surgery, laser ablation (laser interstitial thermal therapy [LITT]), and continued medications

[406]

Consultation with an advisory group of four patients with drug-resistant epilepsy

1. Surgical options [Open brain surgery, Laser surgery]

2. Probability of being seizure free for at least 2 years [70%, 60%, 40%, 20%]

4. Probability of 30-day mortality [0%, 1%, 5%, 10%]

4. Probability of long-term problems after surgery [0%, 10%, 20%, 40%]

Rosenow, 2022, 8 European countries [27]

To elicit patients' preferences for attributes characterizing AEDs monotherapy options before treatment consultation, and to explore the trade-offs patients consider between treatment efficacy and risks of side effects. [404: 310 patients, 94 physicians]

Five experts—four physicians and one patient ambassador selected 7 attributes from a list of 15. The 15 attributes were selected by the funders’ staff from a list of 67 attributes. The source of the original 67 attributes was not explained

1. Chance of becoming seizure-free [60% chance, 45% chance, 25% chance]

2. Chance of developing clinical depression [None, 4% chance, 10% chance]

3. Personality changes [None, Mild, Moderate to severe]

4. Trouble thinking clearly [None, Mild, Moderate to severe]

5. Dizziness [None, Mild, Moderate to severe]

6. Change in body weight in 6 months [5% weight loss, No change, 5% weight gain]

7. Feeling sleepy or tired [None, Sleepiness, Mild-to-moderate tiredness, Severe tiredness]