gms | German Medical Science

Background: Multimedication in connection with multimorbidity is focused on older patients and offers many challenges in medical care. We will consider empirical results of the 5 year survival rate of patients with multimedication compared with other patients. Short and long time changes in the number of different prescribed drugs are reflecting aspects of drug efficiency, compliance and safety.

Materials and Methods: We examined drug prescription data with respect to § 301 SGB V of regional statutory health insurances from 2006 to 2011. We used the international ATC (anatomical therapeutic chemical) classification. Active substances were defined in the sense of an ATC 7 digit code. We used multimedication in the sense of at least 7 different active substances prescribed within a quarter.

Results: We concentrate on the data of patients at least 65 years old with drug prescriptions in 2006 and consider, if there are drug prescriptions for them in 2011. We exclude those persons, which can’t be followed during the whole time due to fusions of health insurances and therefore change in pseudonyms. We use this re-identification in order to get an estimator for age dependent 5 year survival rates. The patients who got at least 7 different active substances in each quarter of 2006 have as an average over the age only 20% lower survival rates. If we take into account that those persons are multi morbid ones one can state, that the drug prescriptions are on the whole successfully. Nevertheless the number of drugs should be reduced, if possible due to interactions and side effects. So it is of large importance, if such reduction can be found in the data. Therefore we analyse, in which way the number of prescribed different active substances changes from one quarter to the next. As an example we look at those patients, which got 7 to 9 different substances in 3/2011. 37.9% of them also got 7 to 9 substances in the following quarter. A larger group of 42.7% only got 1 to 6 substances, an increase to 10 till 14 substances was observed for 14.5%. 3.9% could not be re-identified in the data, this might be used as an estimator of the death rate. A change of the individual health insurance would have the same effect, but plays a minor role in a short time for elderly persons. As another example the modal value of prescribed different substances in the subsequently quarter is 9, if in the quarter before exactly 10 different substances were prescribed. So a reduction tendency can be observed. In these consideration all prescription for one person were used regardless of the physician. Next we examine long range prescription changes from 2006 till 2011. We consider patients with a prescription range of at least 12 quarters with a median of at least 7 different active substances quarterly. We are interested, if there is a linear trend or if there are more shortly concentrated acute prescriptions. 50% patients have a linear correlation r^2 of 0.13 or less. Here we have more acute peaks then linear trends. 27% of the patients have r^2 values of 0.3 or more which can be interpreted as linear trends. For the considered group with a prescription period of at least 3 years and maximal 6 years we have a mean increase of 0.05 active substances per quarter. If we demand a median of at least one active substance per quarter instead of 7 active substances we only get an increase of 0.01. So for a longer range we have an increase of the number of different active substances per quarter. The patient individual tendency is different of the group changes from quarter to quarter. As a consequence we have at least no age independent Markov model.

Conclusion: Focused on patients there is a large variation in the multimedication especially for older patients. In the short range a certain reduction of the number of different prescribed active substances is observed. Frequently drugs are only prescribed in the acute treatment. In the long range we observe a slow increase in the number of different prescribed active substances. Multimedication is a main aspect in the individual physician pharmacotherapy counseling performed in the considered German region accomplished by the statutory health insurance and Regional Association of statutory health insurance Accredited Physicians.