Although tolvaptan has specific side effects and is not primarily essential for survival, a high degree of adherence to tolvaptan therapy became apparent in the pivotal TEMPO 3:4 and TEMPO 4:4 trials in patients with ADPKD [14, 16]. Therefore, we wanted to examine the adherence and the satisfaction with information received about tolvaptan in our ADPKD patients with 10 years of tolvaptan treatment. To the best of our knowledge, our group of 12 ADPKD patients, with a mean tolvaptan treatment duration of 10.2 years, is the largest reported cohort up to now in this regard. The mean daily dosage of 90 mg tolvaptan corresponded to the average dosage of 95 mg per day in the verum group of TEMPO 3:4  and a median Irazabal-classification of 1D was indicative for the presence of rapidly progressive ADPKD . People with ADPKD are often highly motivated patients because they know the scenario of end-stage renal failure from their relatives. Nevertheless, non-adherence in patients usually increases over time of medication intake with a considerable side effect profile and may hereby challenge the long-term treatment effects of tolvaptan. Nevertheless, the MARS-D sum score of the patients amounted to 23.5 points (maximum possible score: 25 points), thus demonstrating the consistently high degree of tolvaptan adherence even after 10.2 years of treatment. This result is in line with Edwards et al. who reported on a group of ADPKD patients in whom only 1 in 39 patients with more than five years of tolvaptan treatment (group average tolvaptan treatment period: 7.6 years) discontinued tolvaptan due to an adverse event . Interestingly, 50 % of the patients stated that they rarely suspend the intake of tolvaptan and one third of the patients stated that they rarely or sometimes skip a single dose of tolvaptan on purpose. Maybe, this can be partly explained by occasional changes in patients’ condition such as diarrhea, fever or lack of access to water. Moreover, due to the permanent polyuria and polydipsia, it is understandable to skip a single dose of tolvaptan on purpose in everyday issues such as important personal or business appointments, shift changes, flights or long-distance freeway journeys. Since patients deal with diseases differently, they also need different information about prescribed medications on an individual basis [22, 24]. Therefore, examination of satisfaction with the information received about tolvaptan could open up the possibility of adapting this information to the individual needs of ADPKD patients. The evaluation of the SIMS-D AU resulted in an average of 9 points (maximum possible score: 9 points) with a range of only 1 point, and thus indicated a high level of satisfaction with the information received about the action and usage of tolvaptan. However, there was a single patient who, even after taking tolvaptan for 10 years, stated that he had not received any information about how to recognize the effects of tolvaptan. As mentioned above, the provision of information by doctors should aim to meet the preferences of the individual patient, but of course every patient should receive a certain minimum amount of basic information. In contrast to the SIMS-D AU, the evaluation of the SIMS-D PP revealed a clearly measureable level of dissatisfaction regarding the information received about potential problems with tolvaptan in 42 % of the patients. Although the overall score of the SIMS-PP amounted to the maximum possible score of 8 points, there was a rather big range of 6 points. In fact, one third of the patients were dissatisfied with the information received about the risk of tolvaptan-related side effects such as drowsiness, sex life impairment, or potential drug interactions. This result suggests that concerns about tolvaptan-related side effects are common in ADPKD patients, even after 10 years of tolvaptan treatment. Notwithstanding, a lack of information about side effects is certainly a missed opportunity to reassure patients, while patients who are concerned anyway may become even more dissatisfied with their situation. Recently, Joly et al. reported on baseline results from the ACQUIRE study (ClinicalTrials.gov Identifier NCT02848521) that collects ADPKD-specific health-related quality of life and treatment satisfaction data in 385 ADPKD patients (45 % of them with tolvaptan treatment) . In ACQUIRE, the mean “global treatment satisfaction” was scored 58, 68, and 67 for CKD stage 1, 2, and 3 with the abbreviated Treatment Satisfaction Questionnaire for Medication (TSQM-9, score range: 0 to 100) . However, the TSQM-9 neither examines satisfaction with the medical information received nor influence of drug side effects on treatment satisfaction like the original TSQM . Nevertheless, and in accordance with our results from the SIMS-D PP subscale, a “two-thirds rating” of "global treatment satisfaction" indicates the need for improvement in the care of patients with ADPKD. Of course, the required monthly check intervals after starting tolvaptan for a total of 18 months are very favorable in order to detect possible side effects such as hypohydration or an increase in hepatic enzymes. But during this period, not only the titration of the maximum tolerated dosage of tolvaptan, but also a standardized survey of the patients about their satisfaction with tolvaptan and the information received about it should be performed at least once. As the SIMS takes into account individual differences by eliciting the patients’ own views about the medication information received, it could be used as a measurement tool in clinical practice to evaluate the individual information needs to facilitate optimal patient satisfaction with tolvaptan . Unexpectedly, the mean annual slope of eGFR accelerated from − 2.7 ± 1.3 ml/min/1.73 m2 per year during the TEMPO period to -4.5 ± 2.6 ml/min/1.73 m2 per year during the Jinarc® period. Recently, Yu et al. have shown that the long-term decline of eGFR in ADPKD patients accelerated in later life and was associated with the baseline Irazabal-subclass . However, this association was not absolutely constant in our small cohort of tolvaptan-treated ADPKD patients, and a detailed examination revealed that an acceleration in the annual slope of eGFR could be observed especially in individuals whose drug therapy for arterial hypertension had to be intensified during the Jinarc® period. For this purpose, the inhibition of the renin-angiotensin-aldosterone system (RAAS) was primarily maximized, to which these patients probably reacted particularly sensitively and therefore possibly showed a decrease in eGFR, as has already been reported by Schrier et al. in this context . Accordingly, there was also a significant correlation of the difference in the annual slope of eGFR between the TEMPO and the Jinarc® period with the change in mean arterial and systolic blood pressure during the Jinarc® period. In view of the small size of our study population, this effect, which probably only occurred in a few patients, may nevertheless have led to a bias in the annual slope of eGFR. Considering the mean annual slope of eGFR of -2.72 ml/min/1.73 m2 per year in TEMPO 3:4  and − 3.14 to -3.26 ml/min/1.73 m2 per year in TEMPO 4:4 , the reasons for the poorer course in the mean annual slope of eGFR during the Jinarc® period were therefore probably the progression of ADPKD and a bias due to the intensification of blood pressure therapy in individual patients. The small number of patients, the monocentricity, only one examination during the trial and the fact that adherence was self-reported, are noteworthy limitations of our study. As a self-reported study, there may be differences between the actual behavior of patients and what they reported in the MARS-D and future adherence-studies in this population may need to combine a self-reported measure with other techniques like pill counting.