<select v-model="disease_history.doctor" class="form-control col-2">
<option v-for="user in users" :value="user.id" :selected="user.id === disease_history.doctor.id">{>user.last_name<} {>user.last_name[0]<}.
{>user.last_name[0]<}.
</option>
</select>
user.id === disease_history.doctor.id
возвращает true