Symptom-specific thresholds for testosterone deficiency modulate complaints and metabolic risk in 434 aging male patients
M Zitzmann, S Faber & E Nieschlag
Objective: The structure of psychological and somatic complaints of aging male patients in relation to sex hormone patterns and metabolism has not been fully elucidated, especially in regard to late-onset hypogonadism.
Methods: We investigated the nature of complaints in 434 consecutive patients aged 5086 years attending our andrology unit and their association with physical characteristics, life style habits and sex hormone levels.
Results: Three independent patient profiles were identified by two-step cluster analysis: 1. psychosomatic complaints, 2. somatic disorders and 3. complaints restricted to sexual problems. Age and BMI were higher in cluster 2 while total testosterone (T) concentrations were lower in cluster 1 and higher in cluster 3 compared to the total cohort. The relation of complaints and metabolic risk factors to T was non-linear and symptom-specific, forming a plateau in patient groups with higher levels of T and causing respective prevalence to increase below specific cut-offs: <8 nmol/l: hot flushes, erectile dysfunction; <10 nmol/l: feeling depressed, lacking concentration, diabetes mellitus type 2; <12 nmol/l: obesity (Body Mass Index ≥ 30 kg×m−2, 15 nmol/l: loss of libido, loss of vigor. Also within the subgroup of non-obese men, diabetes mellitus type 2 was more likely to be present in case of T levels below 10 nmol/l. Erectile dysfunction was a major complaint in 59% of all patients and independently caused by cigarette smoking (P< 0.001) as well as T<8 nmol/l (P<0.001) in binomial regression models.
Conclusion: Older men seeking andrological advice form 3 major patient groups in regard to psychosomatic complaints, metabolic risk and sexual function. Symptoms relate to T in a non-linear, symptom-specific manner. In individual patients, occurance of symptoms related to late-onset hypogonadism may have specific thresholds of T levels.