Context : Multiwavelength monitoring of Be/X-ray binaries is crucial to understand the mechanisms producing their outbursts .
H 1145–619 is one of these systems , which has recently displayed X-ray activity .

Aims : We investigate the correlation between the optical emission and X-ray activity to predict the occurrence of new X-ray outbursts from the inferred state of the circumstellar disc .

Methods : We have performed a multiwavelength study of H 1145–619 from 1973 to 2017 and present here a global analysis of its variability over the last 40 years .
We used optical spectra from the SAAO , SMARTS , and SALT telescopes and optical photometry from the Optical Monitoring Camera ( OMC ) onboard INTEGRAL and from the All Sky Automated Survey ( ASAS ) .
We also used X-ray observations from INTEGRAL /JEM–X , and IBIS to generate the light curves and combined them with Swift /XRT to extract the X-ray spectra .
In addition , we compiled archival observations and measurements from the literature to complement these data .

Results : Comparing the evolution of the optical continuum emission with the H \alpha line variability , we identified three different patterns of optical variability : first , global increases and decreases of the optical brightness , observed from 1982 to 1994 and from 2009 to 2017 , which can be explained by the dissipation and replenishment of the circumstellar disc ; second , superorbital variations with a period of P _ { superorb } \approx 590 days , observed in 2002–2009 , which seems to be related to the circumstellar disc ; and third , optical outbursts , observed in 1998–1999 and 2002–2005 , which we interpret as mass ejections from the Be star .
We discovered the presence of a retrograde one-armed density wave , which appeared in 2016 and is still present in the circumstellar disc .

Conclusions : We carried out the most complete long-term optical study of the Be/X-ray binary H 1145-619 in correlation with its X-ray activity .
For the first time , we found the presence of a retrograde density perturbation in the circumstellar disc of a Be/X-ray binary .